結果

問題 No.1301 Strange Graph Shortest Path
コンテスト
ユーザー gew1fw
提出日時 2025-06-12 21:06:17
言語 PyPy3
(7.3.15)
結果
WA  
実行時間 -
コード長 2,532 bytes
コンパイル時間 254 ms
コンパイル使用メモリ 81,920 KB
実行使用メモリ 162,852 KB
最終ジャッジ日時 2025-06-12 21:08:57
合計ジャッジ時間 24,715 ms
ジャッジサーバーID
（参考情報） 		judge2 / judge3
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ファイルパターン 結果
sample AC * 2
other AC * 27 WA * 4 TLE * 1 -- * 1
権限があれば一括ダウンロードができます

ソースコード

diff # 

import sys
import heapq

def main():
    input = sys.stdin.read().split()
    idx = 0
    N = int(input[idx])
    idx += 1
    M = int(input[idx])
    idx += 1

    edges = []
    adj = [[] for _ in range(N+1)]
    for _ in range(M):
        u = int(input[idx])
        idx += 1
        v = int(input[idx])
        idx += 1
        c = int(input[idx])
        idx += 1
        d = int(input[idx])
        idx += 1
        edges.append((u, v, c, d))
        adj[u].append((v, c, d))
        adj[v].append((u, c, d))

    # Step 1: Find the minimal 1->N path
    def dijkstra(start, end, adj):
        dist = [float('inf')] * (N+1)
        dist[start] = 0
        heap = [(0, start)]
        parent = [-1] * (N+1)
        visited = [False] * (N+1)

        while heap:
            current_dist, u = heapq.heappop(heap)
            if visited[u]:
                continue
            visited[u] = True
            if u == end:
                break
            for v, c, d in adj[u]:
                if not visited[v] and dist[v] > current_dist + c:
                    dist[v] = current_dist + c
                    heapq.heappush(heap, (dist[v], v))
                    parent[v] = u

        path = []
        u = end
        while u != start:
            prev = parent[u]
            if prev == -1:
                break
            path.append((prev, u))
            u = prev
        path.reverse()
        return dist[end], path

    min_dist_1n, path_1n_edges = dijkstra(1, N, adj)
    if min_dist_1n == float('inf'):
        print(-1)
        return

    # Extract the edges used in the path
    edge_set = set()
    for u, v in path_1n_edges:
        for e in edges:
            a, b, _, _ = e
            if (a == u and b == v) or (a == v and b == u):
                edge_set.add((u, v, e[2], e[3]))
                break

    # Build the modified adjacency list for the return path
    modified_adj = [[] for _ in range(N+1)]
    for e in edges:
        u, v, c, d = e
        if (u, v, c, d) in edge_set or (v, u, c, d) in edge_set:
            modified_adj[u].append((v, d, c))
            modified_adj[v].append((u, d, c))
        else:
            modified_adj[u].append((v, c, d))
            modified_adj[v].append((u, c, d))

    # Run Dijkstra again for the return path from N to 1 with modified edges
    min_dist_n1, _ = dijkstra(N, 1, modified_adj)
    if min_dist_n1 == float('inf'):
        print(-1)
        return

    total = min_dist_1n + min_dist_n1
    print(total)

if __name__ == '__main__':
    main()
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