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2017/10/10.md
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@ -123,7 +123,7 @@ Once the rounds are complete, you will be left with the numbers from `0`
to `255` in some order, called the *sparse hash*. Your next task is to to `255` in some order, called the *sparse hash*. Your next task is to
reduce these to a list of only `16` numbers called the *dense hash*. To reduce these to a list of only `16` numbers called the *dense hash*. To
do this, use numeric bitwise do this, use numeric bitwise
[XOR](https://en.wikipedia.org/wiki/Bitwise_operation#XOR) to combine [](https://en.wikipedia.org/wiki/Bitwise_operation#) to combine
each consecutive block of `16` numbers in the sparse hash (there are each consecutive block of `16` numbers in the sparse hash (there are
`16` such blocks in a list of `256` numbers). So, the first element in `16` such blocks in a list of `256` numbers). So, the first element in
the dense hash is the first sixteen elements of the sparse hash XOR\'d the dense hash is the first sixteen elements of the sparse hash XOR\'d

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## \-\-- Day 20: Race Condition \-\--
The Historians are quite pixelated again. This time, a massive, black
building looms over you - you\'re [right outside](/2017/day/24) the CPU!
While The Historians get to work, a nearby program sees that you\'re
idle and challenges you to a *race*. Apparently, you\'ve arrived just in
time for the frequently-held *race condition* festival!
The race takes place on a particularly long and twisting code path;
programs compete to see who can finish in the *fewest picoseconds*. The
winner
even gets their very own
[mutex](https://en.wikipedia.org/wiki/Lock_(computer_science))!
They hand you a *map of the racetrack* (your puzzle input). For example:
###############
#...#...#.....#
#.#.#.#.#.###.#
#S#...#.#.#...#
#######.#.#.###
#######.#.#...#
#######.#.###.#
###..E#...#...#
###.#######.###
#...###...#...#
#.#####.#.###.#
#.#...#.#.#...#
#.#.#.#.#.#.###
#...#...#...###
###############
The map consists of track (`.`) - including the *start* (`S`) and *end*
(`E`) positions (both of which also count as track) - and *walls* (`#`).
When a program runs through the racetrack, it starts at the start
position. Then, it is allowed to move up, down, left, or right; each
such move takes *1 picosecond*. The goal is to reach the end position as
quickly as possible. In this example racetrack, the fastest time is `84`
picoseconds.
Because there is only a single path from the start to the end and the
programs all go the same speed, the races used to be pretty boring. To
make things more interesting, they introduced a new rule to the races:
programs are allowed to *cheat*.
The rules for cheating are very strict. *Exactly once* during a race, a
program may *disable collision* for up to *2 picoseconds*. This allows
the program to *pass through walls* as if they were regular track. At
the end of the cheat, the program must be back on normal track again;
otherwise, it will receive a [segmentation
fault](https://en.wikipedia.org/wiki/Segmentation_fault)
and get disqualified.
So, a program could complete the course in 72 picoseconds (saving *12
picoseconds*) by cheating for the two moves marked `1` and `2`:
###############
#...#...12....#
#.#.#.#.#.###.#
#S#...#.#.#...#
#######.#.#.###
#######.#.#...#
#######.#.###.#
###..E#...#...#
###.#######.###
#...###...#...#
#.#####.#.###.#
#.#...#.#.#...#
#.#.#.#.#.#.###
#...#...#...###
###############
Or, a program could complete the course in 64 picoseconds (saving *20
picoseconds*) by cheating for the two moves marked `1` and `2`:
###############
#...#...#.....#
#.#.#.#.#.###.#
#S#...#.#.#...#
#######.#.#.###
#######.#.#...#
#######.#.###.#
###..E#...12..#
###.#######.###
#...###...#...#
#.#####.#.###.#
#.#...#.#.#...#
#.#.#.#.#.#.###
#...#...#...###
###############
This cheat saves *38 picoseconds*:
###############
#...#...#.....#
#.#.#.#.#.###.#
#S#...#.#.#...#
#######.#.#.###
#######.#.#...#
#######.#.###.#
###..E#...#...#
###.####1##.###
#...###.2.#...#
#.#####.#.###.#
#.#...#.#.#...#
#.#.#.#.#.#.###
#...#...#...###
###############
This cheat saves *64 picoseconds* and takes the program directly to the
end:
###############
#...#...#.....#
#.#.#.#.#.###.#
#S#...#.#.#...#
#######.#.#.###
#######.#.#...#
#######.#.###.#
###..21...#...#
###.#######.###
#...###...#...#
#.#####.#.###.#
#.#...#.#.#...#
#.#.#.#.#.#.###
#...#...#...###
###############
Each cheat has a distinct *start position* (the position where the cheat
is activated, just before the first move that is allowed to go through
walls) and *end position*; cheats are uniquely identified by their start
position and end position.
In this example, the total number of cheats (grouped by the amount of
time they save) are as follows:
- There are 14 cheats that save 2 picoseconds.
- There are 14 cheats that save 4 picoseconds.
- There are 2 cheats that save 6 picoseconds.
- There are 4 cheats that save 8 picoseconds.
- There are 2 cheats that save 10 picoseconds.
- There are 3 cheats that save 12 picoseconds.
- There is one cheat that saves 20 picoseconds.
- There is one cheat that saves 36 picoseconds.
- There is one cheat that saves 38 picoseconds.
- There is one cheat that saves 40 picoseconds.
- There is one cheat that saves 64 picoseconds.
You aren\'t sure what the conditions of the racetrack will be like, so
to give yourself as many options as possible, you\'ll need a list of the
best cheats. *How many cheats would save you at least 100 picoseconds?*
To begin, [get your puzzle input](20/input).
Answer:

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#!/bin/python3
import sys,time,re,copy
from pprint import pprint
sys.path.insert(0, '../../')
from fred import list2int,get_re,nprint,lprint,loadFile,dijkstra,toGrid,findInGrid,create_graph_from_grid,get_value_in_direction,addTuples
start_time = time.time()
input_f = 'input'
#########################################
# #
# Part 1 #
# #
#########################################
def part1():
grid = toGrid(input_f)
start = findInGrid(grid,'S')
end = findInGrid(grid,'E')
graph = create_graph_from_grid(grid,start,end,'#')
#nprint(grid)
grid[start[0]][start[1]] = '.'
grid[end[0]][end[1]] = '.'
path, dist = dijkstra(graph,start,end)
cheatWalls = []
for r,row in enumerate(grid):
for c,pos in enumerate(row):
if pos == '.':
if get_value_in_direction(grid,(r,c),'up') == '#' and get_value_in_direction(grid,(r,c),'down') == '#':
cheatWalls.append(addTuples((r,c),(-1,0)))
cheatWalls.append(addTuples((r,c),(1,0)))
elif get_value_in_direction(grid,(r,c),'left') == '#' and get_value_in_direction(grid,(r,c),'right') == '#':
cheatWalls.append(addTuples((r,c),(0,-1)))
cheatWalls.append(addTuples((r,c),(0,1)))
if pos == '#':
if get_value_in_direction(grid,(r,c),'up') == '.' and get_value_in_direction(grid,(r,c),'down') == '.':
cheatWalls.append((r,c))
cheatWalls.append((r,c))
elif get_value_in_direction(grid,(r,c),'left') == '.' and get_value_in_direction(grid,(r,c),'right') == '.':
cheatWalls.append((r,c))
cheatWalls.append((r,c))
#print(dist)
#nprint(grid,positions=path)
results = {}
startDist = dist
#print(cheatWalls)
for c in cheatWalls:
newGrid = copy.deepcopy(grid)
newGrid[c[0]][c[1]] = '.'
graph = create_graph_from_grid(newGrid,start,end,'#')
path, dist = dijkstra(graph,start,end)
dist = startDist-dist
if dist not in results:
results[dist] = 0
results[dist] += 1
pprint(results)
start_time = time.time()
print('Part 1:',part1(), '\t\t', round((time.time() - start_time)*1000), 'ms')
#########################################
# #
# Part 2 #
# #
#########################################
def part2():
return
start_time = time.time()
print('Part 2:',part2(), '\t\t', round((time.time() - start_time)*1000), 'ms')

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## \-\-- Day 23: LAN Party \-\--
As The Historians wander around a secure area at Easter Bunny HQ, you
come across posters for a [LAN
party](https://en.wikipedia.org/wiki/LAN_party)
scheduled for today! Maybe you can find it; you connect to a nearby
[datalink port](/2016/day/9) and download a map of the local network
(your puzzle input).
The network map provides a list of every *connection between two
computers*. For example:
kh-tc
qp-kh
de-cg
ka-co
yn-aq
qp-ub
cg-tb
vc-aq
tb-ka
wh-tc
yn-cg
kh-ub
ta-co
de-co
tc-td
tb-wq
wh-td
ta-ka
td-qp
aq-cg
wq-ub
ub-vc
de-ta
wq-aq
wq-vc
wh-yn
ka-de
kh-ta
co-tc
wh-qp
tb-vc
td-yn
Each line of text in the network map represents a single connection; the
line `kh-tc` represents a connection between the computer named `kh` and
the computer named `tc`. Connections aren\'t directional; `tc-kh` would
mean exactly the same thing.
LAN parties typically involve multiplayer games, so maybe you can locate
it by finding groups of connected computers. Start by looking for *sets
of three computers* where each computer in the set is connected to the
other two computers.
In this example, there are `12` such sets of three inter-connected
computers:
aq,cg,yn
aq,vc,wq
co,de,ka
co,de,ta
co,ka,ta
de,ka,ta
kh,qp,ub
qp,td,wh
tb,vc,wq
tc,td,wh
td,wh,yn
ub,vc,wq
If the Chief Historian is here, *and* he\'s at the LAN party, it would
be best to know that right away. You\'re pretty sure his computer\'s
name starts with `t`, so consider only sets of three computers where at
least one computer\'s name starts with `t`. That narrows the list down
to `7` sets of three inter-connected computers:
co,de,ta
co,ka,ta
de,ka,ta
qp,td,wh
tb,vc,wq
tc,td,wh
td,wh,yn
Find all the sets of three inter-connected computers. *How many contain
at least one computer with a name that starts with `t`?*
To begin, [get your puzzle input](23/input).
Answer:

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#!/bin/python3
import sys,time,re
from pprint import pprint
sys.path.insert(0, '../../')
from fred import list2int,get_re,nprint,lprint,loadFile,dprint,TSP,dfs_graph
start_time = time.time()
input_f = 'test'
#########################################
# #
# Part 1 #
# #
#########################################
def part1():
graph = {}
file = loadFile(input_f)
for f in file:
f = f.split('-')
if f[0] not in graph:
graph[f[0]] = []
if f[1] not in graph:
graph[f[1]] = []
graph[f[0]].append(f[1])
graph[f[1]].append(f[0])
dprint(graph)
for key,values in graph.items():
print(key)
print(dfs_graph(graph,key))
input()
start_time = time.time()
print('Part 1:',part1(), '\t\t', round((time.time() - start_time)*1000), 'ms')
#########################################
# #
# Part 2 #
# #
#########################################
def part2():
return
start_time = time.time()
print('Part 2:',part2(), '\t\t', round((time.time() - start_time)*1000), 'ms')

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## \-\-- Day 24: Crossed Wires \-\--
You and The Historians arrive at the edge of a [large
grove](/2022/day/23) somewhere in the jungle. After the last incident,
the Elves installed a small device that monitors the fruit. While The
Historians search the grove, one of them asks if you can take a look at
the monitoring device; apparently, it\'s been malfunctioning recently.
The device seems to be trying to produce a number through some boolean
logic gates. Each gate has two inputs and one output. The gates all
operate on values that are either *true* (`1`) or *false* (`0`).
- `AND` gates output `1` if *both* inputs are `1`; if either input is
`0`, these gates output `0`.
- `OR` gates output `1` if *one or both* inputs is `1`; if both inputs
are `0`, these gates output `0`.
- `XOR` gates output `1` if the inputs are *different*; if the inputs
are the same, these gates output `0`.
Gates wait until both inputs are received before producing output; wires
can carry `0`, `1` or no value at all. There are no loops; once a gate
has determined its output, the output will not change until the whole
system is reset. Each wire is connected to at most one gate output, but
can be connected to many gate inputs.
Rather than risk getting shocked while tinkering with the live system,
you write down all of the gate connections and initial wire values (your
puzzle input) so you can consider them in relative safety. For example:
x00: 1
x01: 1
x02: 1
y00: 0
y01: 1
y02: 0
x00 AND y00 -> z00
x01 XOR y01 -> z01
x02 OR y02 -> z02
Because gates wait for input, some wires need to start with a value (as
inputs to the entire system). The first section specifies these values.
For example, `x00: 1` means that the wire named `x00` starts with the
value `1` (as if a gate is already outputting that value onto that
wire).
The second section lists all of the gates and the wires connected to
them. For example, `x00 AND y00 -> z00` describes an instance of an
`AND` gate which has wires `x00` and `y00` connected to its inputs and
which will write its output to wire `z00`.
In this example, simulating these gates eventually causes `0` to appear
on wire `z00`, `0` to appear on wire `z01`, and `1` to appear on wire
`z02`.
Ultimately, the system is trying to produce a *number* by combining the
bits on all wires starting with `z`. `z00` is the least significant bit,
then `z01`, then `z02`, and so on.
In this example, the three output bits form the binary number `100`
which is equal to the decimal number `4`.
Here\'s a larger example:
x00: 1
x01: 0
x02: 1
x03: 1
x04: 0
y00: 1
y01: 1
y02: 1
y03: 1
y04: 1
ntg XOR fgs -> mjb
y02 OR x01 -> tnw
kwq OR kpj -> z05
x00 OR x03 -> fst
tgd XOR rvg -> z01
vdt OR tnw -> bfw
bfw AND frj -> z10
ffh OR nrd -> bqk
y00 AND y03 -> djm
y03 OR y00 -> psh
bqk OR frj -> z08
tnw OR fst -> frj
gnj AND tgd -> z11
bfw XOR mjb -> z00
x03 OR x00 -> vdt
gnj AND wpb -> z02
x04 AND y00 -> kjc
djm OR pbm -> qhw
nrd AND vdt -> hwm
kjc AND fst -> rvg
y04 OR y02 -> fgs
y01 AND x02 -> pbm
ntg OR kjc -> kwq
psh XOR fgs -> tgd
qhw XOR tgd -> z09
pbm OR djm -> kpj
x03 XOR y03 -> ffh
x00 XOR y04 -> ntg
bfw OR bqk -> z06
nrd XOR fgs -> wpb
frj XOR qhw -> z04
bqk OR frj -> z07
y03 OR x01 -> nrd
hwm AND bqk -> z03
tgd XOR rvg -> z12
tnw OR pbm -> gnj
After waiting for values on all wires starting with `z`, the wires in
this system have the following values:
bfw: 1
bqk: 1
djm: 1
ffh: 0
fgs: 1
frj: 1
fst: 1
gnj: 1
hwm: 1
kjc: 0
kpj: 1
kwq: 0
mjb: 1
nrd: 1
ntg: 0
pbm: 1
psh: 1
qhw: 1
rvg: 0
tgd: 0
tnw: 1
vdt: 1
wpb: 0
z00: 0
z01: 0
z02: 0
z03: 1
z04: 0
z05: 1
z06: 1
z07: 1
z08: 1
z09: 1
z10: 1
z11: 0
z12: 0
Combining the bits from all wires starting with `z` produces the binary
number `0011111101000`. Converting this number to decimal produces
`2024`.
Simulate the system of gates and wires. *What decimal number does it
output on the wires starting with `z`?*
Your puzzle answer was `51715173446832`.
The first half of this puzzle is complete! It provides one gold star: \*
## \-\-- Part Two \-\-- {#part2}
After inspecting the monitoring device more closely, you determine that
the system you\'re simulating is trying to *add two binary numbers*.
Specifically, it is treating the bits on wires starting with `x` as one
binary number, treating the bits on wires starting with `y` as a second
binary number, and then attempting to add those two numbers together.
The output of this operation is produced as a binary number on the wires
starting with `z`. (In all three cases, wire `00` is the least
significant bit, then `01`, then `02`, and so on.)
The initial values for the wires in your puzzle input represent *just
one instance* of a pair of numbers that sum to the wrong value.
Ultimately, *any* two binary numbers provided as input should be handled
correctly. That is, for any combination of bits on wires starting with
`x` and wires starting with `y`, the sum of the two numbers those bits
represent should be produced as a binary number on the wires starting
with `z`.
For example, if you have an addition system with four `x` wires, four
`y` wires, and five `z` wires, you should be able to supply any four-bit
number on the `x` wires, any four-bit number on the `y` numbers, and
eventually find the sum of those two numbers as a five-bit number on the
`z` wires. One of the many ways you could provide numbers to such a
system would be to pass `11` on the `x` wires (`1011` in binary) and
`13` on the `y` wires (`1101` in binary):
x00: 1
x01: 1
x02: 0
x03: 1
y00: 1
y01: 0
y02: 1
y03: 1
If the system were working correctly, then after all gates are finished
processing, you should find `24` (`11+13`) on the `z` wires as the
five-bit binary number `11000`:
z00: 0
z01: 0
z02: 0
z03: 1
z04: 1
Unfortunately, your actual system needs to add numbers with many more
bits and therefore has many more wires.
Based on forensic analysis of scuff marks and
scratches on the device, you can tell that there are exactly *four*
pairs of gates whose output wires have been *swapped*. (A gate can only
be in at most one such pair; no gate\'s output was swapped multiple
times.)
For example, the system below is supposed to find the bitwise `AND` of
the six-bit number on `x00` through `x05` and the six-bit number on
`y00` through `y05` and then write the result as a six-bit number on
`z00` through `z05`:
x00: 0
x01: 1
x02: 0
x03: 1
x04: 0
x05: 1
y00: 0
y01: 0
y02: 1
y03: 1
y04: 0
y05: 1
x00 AND y00 -> z05
x01 AND y01 -> z02
x02 AND y02 -> z01
x03 AND y03 -> z03
x04 AND y04 -> z04
x05 AND y05 -> z00
However, in this example, two pairs of gates have had their output wires
swapped, causing the system to produce wrong answers. The first pair of
gates with swapped outputs is `x00 AND y00 -> z05` and
`x05 AND y05 -> z00`; the second pair of gates is `x01 AND y01 -> z02`
and `x02 AND y02 -> z01`. Correcting these two swaps results in this
system that works as intended for any set of initial values on wires
that start with `x` or `y`:
x00 AND y00 -> z00
x01 AND y01 -> z01
x02 AND y02 -> z02
x03 AND y03 -> z03
x04 AND y04 -> z04
x05 AND y05 -> z05
In this example, two pairs of gates have outputs that are involved in a
swap. By sorting their output wires\' names and joining them with
commas, the list of wires involved in swaps is `z00,z01,z02,z05`.
Of course, your actual system is much more complex than this, and the
gates that need their outputs swapped could be *anywhere*, not just
attached to a wire starting with `z`. If you were to determine that you
need to swap output wires `aaa` with `eee`, `ooo` with `z99`, `bbb` with
`ccc`, and `aoc` with `z24`, your answer would be
`aaa,aoc,bbb,ccc,eee,ooo,z24,z99`.
Your system of gates and wires has *four* pairs of gates which need
their output wires swapped - *eight* wires in total. Determine which
four pairs of gates need their outputs swapped so that your system
correctly performs addition; *what do you get if you sort the names of
the eight wires involved in a swap and then join those names with
commas?*
Answer:
Although it hasn\'t changed, you can still [get your puzzle
input](24/input).

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#!/bin/python3
import sys,time,re
from pprint import pprint
sys.path.insert(0, '../../')
from fred import list2int,get_re,nprint,lprint,loadFile,dprint
start_time = time.time()
input_f = 'input'
def loadGates(input_f):
gates = {}
instructions = []
with open(input_f) as file:
for line in file:
if ':' in line:
tmp = line.split(': ')
gates[tmp[0]] = int(tmp[1])
if '->' in line:
tmp = line.replace('-> ','').rstrip().split(' ')
instructions.append(tmp)
return gates, instructions
#########################################
# #
# Part 1 #
# #
#########################################
def part1():
gates, instructions = loadGates(input_f)
#print(gates)
#print(instructions)
wait_for = []
for inst in instructions:
x,logic,y,z = inst
if x not in gates or y not in gates:
#print(inst)
wait_for.append(inst)
continue
for wdx, w in enumerate(wait_for):
x,logic,y,z = w
if x in gates and y in gates:
#print(wait_for,w,wdx)
# `AND` gates output `1` if *both* inputs are `1`; if either input is `0`, these gates output `0`.
if logic == 'AND':
gates[z] = 1 if gates[x] and gates[y] else 0
# `OR` gates output `1` if *one or both* inputs is `1`; if both inputs are `0`, these gates output `0`.
if logic == 'OR':
gates[z] = 1 if gates[x] or gates[y] else 0
# `XOR` gates output `1` if the inputs are *different*; if the inputs are the same, these gates output `0`.
if logic == 'XOR':
gates[z] = 1 if gates[x] != gates[y] else 0
wait_for.pop(wdx)
#input()
x,logic,y,z = inst
# `AND` gates output `1` if *both* inputs are `1`; if either input is `0`, these gates output `0`.
if logic == 'AND':
gates[z] = 1 if gates[x] and gates[y] else 0
# `OR` gates output `1` if *one or both* inputs is `1`; if both inputs are `0`, these gates output `0`.
if logic == 'OR':
gates[z] = 1 if gates[x] or gates[y] else 0
# `XOR` gates output `1` if the inputs are *different*; if the inputs are the same, these gates output `0`.
if logic == 'XOR':
gates[z] = 1 if gates[x] != gates[y] else 0
while len(wait_for) > 0:
for wdx, w in enumerate(wait_for):
x,logic,y,z = w
if x in gates and y in gates:
#print(wait_for,w,wdx)
# `AND` gates output `1` if *both* inputs are `1`; if either input is `0`, these gates output `0`.
if logic == 'AND':
gates[z] = 1 if gates[x] and gates[y] else 0
# `OR` gates output `1` if *one or both* inputs is `1`; if both inputs are `0`, these gates output `0`.
if logic == 'OR':
gates[z] = 1 if gates[x] or gates[y] else 0
# `XOR` gates output `1` if the inputs are *different*; if the inputs are the same, these gates output `0`.
if logic == 'XOR':
gates[z] = 1 if gates[x] != gates[y] else 0
wait_for.pop(wdx)
#dprint(gates)
result = ''
countZ = 0
for g in gates.keys():
if g[0] == 'z':
countZ += 1
for i in range(countZ-1,-1,-1):
#print(i)
#print(g,gates[g])
if i < 10:
result += str(gates['z0'+str(i)])
else:
result += str(gates['z'+str(i)])
print(result)
return int(result, 2)
start_time = time.time()
print('Part 1:',part1(), '\t\t', round((time.time() - start_time)*1000), 'ms')
#########################################
# #
# Part 2 #
# #
#########################################
def part2():
return
start_time = time.time()
print('Part 2:',part2(), '\t\t', round((time.time() - start_time)*1000), 'ms')

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fred.py
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@ -653,6 +653,29 @@ def bfs(start, is_goal, get_neighbors, max_depth=float('inf')):
return goal_nodes, paths_to_goal return goal_nodes, paths_to_goal
def dfs_graph(graph: dict, start) -> list:
"""
Perform a DFS starting from the given position in the graph.
Args:
graph (dict): Dictionary representing the graph where keys are nodes (tuples) and values are lists of neighbors.
start: Starting node in the graph.
Returns:
list: List of visited nodes.
"""
visited = set()
def dfs_graph(node):
visited.add(node)
for neighbor in graph.get(node, []):
if neighbor not in visited:
dfs_graph(neighbor)
dfs_graph(start)
return list(visited)
def dfs(grid:list, pos:set) -> list: def dfs(grid:list, pos:set) -> list:
""" """
Perform a flood fill/dfs starting from the given position in the grid. Perform a flood fill/dfs starting from the given position in the grid.