結果

問題 No.2565 はじめてのおつかい
ユーザー may17
提出日時 2023-12-02 15:56:00
言語 C++17
(gcc 13.3.0 + boost 1.87.0)
結果
AC  
実行時間 153 ms / 2,000 ms
コード長 1,805 bytes
コンパイル時間 2,220 ms
コンパイル使用メモリ 198,792 KB
最終ジャッジ日時 2025-02-18 05:02:07
ジャッジサーバーID
(参考情報)
judge2 / judge2
このコードへのチャレンジ
(要ログイン)
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

#include <bits/stdc++.h>
//#include<atcoder/all>
using namespace std;
//using namespace atcoder;
using ll = long long;
const ll INF = 1000000000000000000LL;
//const ll mod = 998244353;
int n, m, u[100009], v[100009];
vector<int>G[100009];
ll dist[3][100009];
queue<int>Q;
int main() {
cin >> n >> m;
for (int i = 1; i <= m; i++) {
cin >> u[i] >> v[i];
G[u[i]].push_back(v[i]);
}
for (int i = 0; i < 3; i++) {
for (int j = 1; j <= n; j++)dist[i][j] = -1;
}
dist[0][1] = 0;
Q.push(1);
while (!Q.empty()) {
int pos = Q.front(); Q.pop();
for (int i = 0; i < G[pos].size(); i++) {
int nex = G[pos][i];
if (dist[0][nex] == -1) {
dist[0][nex] = dist[0][pos] + 1;
Q.push(nex);
}
}
}
dist[1][n - 1] = 0;
Q.push(n - 1);
while (!Q.empty()) {
int pos = Q.front(); Q.pop();
for (int i = 0; i < G[pos].size(); i++) {
int nex = G[pos][i];
if (dist[1][nex] == -1) {
dist[1][nex] = dist[1][pos] + 1;
Q.push(nex);
}
}
}
dist[2][n] = 0;
Q.push(n);
while (!Q.empty()) {
int pos = Q.front(); Q.pop();
for (int i = 0; i < G[pos].size(); i++) {
int nex = G[pos][i];
if (dist[2][nex] == -1) {
dist[2][nex] = dist[2][pos] + 1;
Q.push(nex);
}
}
}
ll ans1 = INF, ans2 = INF, ans3 = INF;
if (dist[0][n - 1] != -1 && dist[1][n] != -1 && dist[2][1] != -1) {
ans1 = dist[0][n - 1] + dist[1][n] + dist[2][1];
}
if (dist[0][n] != -1 && dist[2][n-1] != -1 && dist[1][1] != -1) {
ans2 = dist[0][n] + dist[2][n-1] + dist[1][1];
}
if (dist[0][n - 1] != -1 && dist[1][1] != -1 && dist[0][n] != -1&&dist[2][1]!=-1) {
ans3 = dist[0][n - 1] + dist[1][1] + dist[0][n]+dist[2][1];
}
//cout << ans1 << " " << ans2 << " " << ans3 << endl;
ll ans = min(ans1, min(ans2, ans3));
if (ans != INF)cout << ans << endl;
else cout << "-1" << endl;
}
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