Solved 2017/24 P1

2017/24/24.md

@@ -59,7 +59,28 @@ a strength of `0+1 + 1+10 + 10+9 = 31`.
 *What is the strength of the strongest bridge you can make* with the
 components you have available?
 
-To begin, [get your puzzle input](24/input).
+Your puzzle answer was `2006`.
+
+The first half of this puzzle is complete! It provides one gold star: \*
+
+## \-\-- Part Two \-\-- {#part2}
+
+The bridge you\'ve built isn\'t long enough; you can\'t [jump the rest
+of the way]{title="Who do you think you are, Mario?"}.
+
+In the example above, there are two longest bridges:
+
+-   `0/2`\--`2/2`\--`2/3`\--`3/4`
+-   `0/2`\--`2/2`\--`2/3`\--`3/5`
+
+Of them, the one which uses the `3/5` component is stronger; its
+strength is `0+2 + 2+2 + 2+3 + 3+5 = 19`.
+
+*What is the strength of the longest bridge you can make?* If you can
+make multiple bridges of the longest length, pick the *strongest* one.
 
 Answer:
 
+Although it hasn\'t changed, you can still [get your puzzle
+input](24/input).
+

2017/24/solution.py

@@ -1,62 +1,47 @@
 #!/bin/python3
 import sys,re
-from copy import deepcopy
 from pprint import pprint
 sys.path.insert(0, '../../')
-from fred import list2int, lprint,get_re
+from fred import list2int,get_re,nprint,lprint
 
-input_f = 'test'
+input_f = 'input'
 
-part = 1
-log = True
+part = 2
 #########################################
 #                                       #
 #              Part 1                   #
 #                                       #
 #########################################
 
-def find_match(comp:list,match:str,result:list):
-    i_match = get_re(r"^(\d+)\/(\d+)$",match)
-    #print(comp,match)
-    comp = [i for i in comp if i != match]
-    #print(comp,result)
-    for i in result:
-        try:
-            comp = [j for j in comp if j != i]
-        except:
-            print(i,'cant be removed from',j)
-    for j in comp:
-        j_match = get_re(r"^(\d+)\/(\d+)$",j)
-        #print(match,j)
-        #input()
-        if i_match.group(2) == j_match.group(1) or i_match.group(2) == j_match.group(2):
-            result.append(j)
-            find_match(comp[:],match,result[:])
-    return result
-
-if part == 1:
-    components = []
+def parse_input(input_f):
+    list_of_components = []
     with open(input_f) as file:
         for line in file:
-            components.append(line.rstrip())
+            l = get_re(r"^(\d+)\/(\d+)$",line.rstrip())
+            list_of_components.append([int(l.group(1)),int(l.group(2))])
+    return list_of_components
 
-    lprint(components,log)
-    original_comp = deepcopy(components)
-    pairs = []
-    result = []
-
-    for i in components[:]:
-        print(i)
-        if i[0] == '0':
-            result.append(find_match(original_comp,i,[i]))
-
-
-    pprint(result)
-    #nput()
-    #lprint(pairs,log)
-    
+def make_bridge(components, last):
+    score = 0
+    longest_bridge = []
+    for cdx, component in enumerate(components):
+        if component[0] == last or component[1] == last:
+            if component[0] == last:
+                tmp = component[1]
+            else:
+                tmp = component[0]
+            x = component + make_bridge(components[:cdx]+components[cdx+1:],tmp)
+            if sum(x) > score:
+                score = sum(x)
+                longest_bridge = x
+    return longest_bridge
 
+if part == 1:
+    components = parse_input(input_f)
+    #print(components)
 
+    bridge = make_bridge(components,0)
+    print(bridge)
 
 
 #########################################
@@ -64,5 +49,31 @@ if part == 1:
 #              Part 2                   #
 #                                       #
 #########################################
+
+def make_bridge_longest(components, last):
+    score = 0
+    longest_bridge = []
+    for cdx, component in enumerate(components):
+        if component[0] == last or component[1] == last:
+            if component[0] == last:
+                tmp = component[1]
+            else:
+                tmp = component[0]
+            x = component + make_bridge(components[:cdx]+components[cdx+1:],tmp)
+            if len(x) > len(longest_bridge) and sum(x) > score:
+                score = sum(x)
+                longest_bridge = x
+                
+    return longest_bridge
+
+
 if part == 2:
-    exit()
+    components = parse_input(input_f)
+    #print(components)
+
+    bridge = make_bridge_longest(components,0)
+
+    print(bridge)
+    #print(sum(bridge))
+
+    #print(sum(bridge))

2017/24/solution_old.py

@@ -0,0 +1,85 @@
+#!/bin/python3
+import sys,re
+from copy import deepcopy
+from pprint import pprint
+sys.path.insert(0, '../../')
+from fred import list2int, lprint,get_re
+
+input_f = 'test'
+
+part = 1
+log = True
+#########################################
+#                                       #
+#              Part 1                   #
+#                                       #
+#########################################
+
+# def find_match(comp:list,match:str,result:list):
+#     #i_match = get_re(r"^(\d+)\/(\d+)$",match)
+#     #print(comp,match)
+#     #comp = [i for i in comp if i != match]
+#     #print(comp,result)
+#     #for i in result:
+#     #    try:
+#     #        comp = [j for j in comp if j != i]
+#     #    except:
+#     #        print(i,'cant be removed from',j)
+#     for j in comp:
+#         j_match = get_re(r"^(\d+)\/(\d+)$",j)
+#         #print(match,j)
+#         #input()
+#         if i_match.group(2) == j_match.group(1) or i_match.group(2) == j_match.group(2):
+#             result.append(j)
+#             find_match(comp[:],match,result[:])
+#     return result
+
+# def find_match(components,match,results):
+#     #print(match,results)
+#     for j in components[:]:
+#         if match[1] == j[0] and j not in results:
+#             results.append(j)
+#             return find_match(components,j,results)
+#     return results
+
+def build_chain(chain:list, components:list):
+    last_componet = chain[len(chain)-1]
+    next_component = None
+    while len(components) > 0:
+        next_component = components.pop()
+        if (
+            next_component[0] == last_componet[1] or 
+            next_component[0] == last_componet[0] or 
+            next_component[1] == last_componet[1] or 
+            next_component[1] == last_componet[0]
+        ):
+            #print(next_component,components)
+
+            chain.append(next_component)
+            build_chain(chain,deepcopy(components))
+    return chain
+
+
+if part == 1:
+    components = []
+    with open(input_f) as file:
+        for line in file:
+            l = get_re(r"^(\d+)\/(\d+)$",line.rstrip())
+            components.append(sorted([int(l.group(1)),int(l.group(2))]))
+
+    pprint(components)
+    original_comp = deepcopy(components)
+
+    for c in components[:]: 
+        if c[0] == 0:
+            chain = build_chain([c],components)
+            print(chain)
+
+
+#########################################
+#                                       #
+#              Part 2                   #
+#                                       #
+#########################################
+if part == 2:
+    exit()

2017/24/test.py

@@ -1,14 +1,33 @@
-from collections import defaultdict
-import pprint
-def build_graph(pairs):
-    graph = defaultdict(list)
-    for pair in pairs:
-        a, b = map(int, pair.split('/'))
-        graph[a].append(b)
-        graph[b].append(a)
+def build_graph(node_list):
+    """
+    Build a graph where:
+    - Each graph starts with a node containing `0`.
+    - Nodes are connected if they share a common value, except `0` cannot connect to another `0`.
+    """
+    graph = {}
+    
+    # Parse nodes
+    parsed_nodes = [tuple(map(int, node.split('/'))) for node in node_list]
+    
+    # Build adjacency list
+    for node1 in parsed_nodes:
+        for node2 in parsed_nodes:
+            # Skip if both nodes contain `0`
+            if node1 == node2 or (0 in node1 and 0 in node2):
+                continue
+            
+            # Add edge if they share a common value
+            if node1[0] == node2[0] or node1[1] == node2[1] or node1[0] == node2[1] or node1[1] == node2[0]:
+                graph.setdefault(node1, []).append(node2)
+                graph.setdefault(node2, []).append(node1)
+    
     return graph
 
-def find_all_paths(graph, start, visited=None, path=None):
+def find_paths(graph, start, visited=None, path=None):
+    """
+    Recursively find all paths starting from a given node.
+    Ensures that each node is visited only once per path.
+    """
     if visited is None:
         visited = set()
     if path is None:
@@ -17,42 +36,32 @@ def find_all_paths(graph, start, visited=None, path=None):
     visited.add(start)
     path.append(start)
 
-    paths = [list(path)]  # Store the current path as a possible connection
-
-    for neighbor in graph[start]:
+    # Print the current path
+    #print(" \--".join(f"{node[0]}/{node[1]}" for node in path))
+    
+    # Explore neighbors
+    for neighbor in graph.get(start, []):
         if neighbor not in visited:
-            paths.extend(find_all_paths(graph, neighbor, visited.copy(), path.copy()))
+            find_paths(graph, neighbor, visited.copy(), path.copy())
+    return path
 
-    return paths
+def main():
+    # Input list of nodes
+    nodes = [
+        "0/2", "2/2", "2/3", "3/4", "3/5", "0/1", "10/1", "9/10"
+    ]
 
-def count_connections(pairs):
-    graph = build_graph(pairs)
-    all_paths = []
+    # Build the graph
+    graph = build_graph(nodes)
+    results = []
+    # Find and print all paths for each subgraph starting with a `0` node
+    zero_nodes = [node for node in graph if 0 in node]
+    for start in zero_nodes:
+        print(f"Starting from {start[0]}/{start[1]}:")
+        tmp = find_paths(graph, start)
+        results.append(tmp)
+    
+    print(results)
 
-    for pair in pairs:
-        a, b = map(int, pair.split('/'))
-        paths_a = find_all_paths(graph, a)
-        paths_b = find_all_paths(graph, b)
-        
-        # Combine paths starting from both nodes in the pair
-        for path in paths_a:
-            if b in path:
-                all_paths.append(path)
-
-        for path in paths_b:
-            if a in path:
-                all_paths.append(path)
-
-    # Remove duplicate paths
-    unique_paths = {tuple(path) for path in all_paths}
-    return len(unique_paths), unique_paths
-
-# Example usage
-pairs = ['0/2','2/2','2/3','3/4','3/5','0/1','10/1','9/10']
-connection_count, connections = count_connections(pairs)
-
-print(f"Number of connections: {connection_count}")
-print("Connections:")
-for connection in connections:
-    print(connection)
-pprint(connections)
+if __name__ == "__main__":
+    main()

2017/24/test2.py

@@ -0,0 +1,36 @@
+import time
+def solve(blocks):
+    new_bridges = [[block] for block in blocks if 0 in block]
+    strongest = 0
+    longest_strength = 0
+    while new_bridges:
+        bridges = new_bridges
+        new_bridges = []
+        for bridge in bridges:
+            new_bridges.extend(list(extend(bridge, blocks)))
+        if new_bridges:
+            longest_strength = max(bridge_strength(bridge) for bridge in new_bridges)
+            strongest = max(strongest, longest_strength)
+    return strongest, longest_strength
+
+def bridge_strength(bridge):
+    return sum(map(sum, bridge))
+
+def extend(bridge, blocks):
+    unused = list(filter(lambda b: b not in bridge and b[::-1] not in bridge, blocks))
+    for block in unused:
+        if bridge[-1][1] == block[0]:
+            yield bridge + [block]
+        elif bridge[-1][1] == block[1]:
+            yield bridge + [block[::-1]]
+
+if __name__ == '__main__':
+    start = time.time()
+    block_list = []
+    with open('input') as f:
+        for line in f:
+            block_list.append(tuple(map(int, line.split('/'))))
+    block_list = [(a, b) if a < b else (b, a) for a, b in block_list]
+
+    print('Part 1: {}\nPart 2: {}'.format(*solve(block_list)))
+    print(f'Solved in {time.time() - start}')

README.md

@@ -62,7 +62,7 @@
 
     .-----------------------------------------------.       
     | o──────*──────┐o┬──────────────────┐┌───────┐ |  25 *
-    | o──*──┐└───┐o─┴─┘o────────┬─────o┌─┘├───o┌──┤ |  24 
+    | o──*──┐└───┐o─┴─┘o────────┬─────o┌─┘├───o┌──┤ |  24 *
     | ┌──┘o─┴────┘┌────────────*├──────┘o─┘┌───┘┌─┘ |  23 *
     | ├───┐┌──────┴o*──|(────┐┌┘└──────────┘o┬──┘o┐ |  22 **
     | └┐o┐└┘*───────┘o┬─┬──┬┴┴┴┬───┬┴┴┴┴┬───┐└────┤ |  21 **