結果

問題 No.2565 はじめてのおつかい
ユーザー RYOH2718
提出日時 2023-12-02 16:09:35
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 491 ms / 2,000 ms
コード長 1,227 bytes
コンパイル時間 498 ms
コンパイル使用メモリ 82,048 KB
実行使用メモリ 94,592 KB
最終ジャッジ日時 2024-09-26 19:54:17
合計ジャッジ時間 17,423 ms
ジャッジサーバーID
(参考情報)
judge1 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 3
other AC * 50
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 #
プレゼンテーションモードにする

def INT():
return int(input())
def MI():
return map(int, input().split())
def LI():
return list(map(int, input().split()))
import heapq
def dijkstra(n, G, start=0):
INF = 10**18
dist = [INF] * n
dist[start] = 0
pq = []
heapq.heappush(pq, (0, start))
visited = [False] * n
while pq:
now = heapq.heappop(pq)[1]
visited[now] = True
for nxt, cost in G[now]:
if dist[nxt] > dist[now] + cost and not visited[nxt]:
dist[nxt] = dist[now] + cost
heapq.heappush(pq, (dist[now] + cost, nxt))
return dist
N, M = MI()
G = [[] for _ in range(N)]
for _ in range(M):
u, v = MI()
u -= 1
v -= 1
G[u].append((v, 1))
dist1 = dijkstra(N, G, 0) # from 0
dist2 = dijkstra(N, G, N - 2) # from N - 2
dist3 = dijkstra(N, G, N - 1) # from N - 1
INF = 10**18
if (dist1[N - 2] == INF or dist2[N - 1] == INF or dist3[0] == INF) or (
dist1[N - 1] == INF or dist3[N - 2] == INF or dist2[0] == INF
):
print(-1)
exit()
cand1 = dist1[N - 2] + dist2[N - 1] + dist3[0]
cand2 = dist1[N - 1] + dist3[N - 2] + dist2[0]
ans = min(cand1, cand2)
print(ans)
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