AcWing 849. Dijkstra求最短路 I
原题链接
简单
作者:
qgc123
,
2021-11-30 19:29:50
,
所有人可见
,
阅读 190
#include<bits/stdc++.h>
using namespace std;
const int N = 510;
int n, m, g[N][N], dist[N];//dist距离 g[N][N]邻接矩阵
bool st[N];
int dijkstra(){
memset(dist, 0x3f, sizeof dist);
dist[1] = 0;
for(int i = 0; i < n; i++){
int t = -1;
for(int j = 1; j <= n; j ++){
if(!st[j] && (t == -1 || dist[t] > dist[j]))
t = j;
}
st[t] = true;
for(int j = 1; j <= n; j++){
dist[j] = min(dist[j], dist[t] + g[t][j]);
}
}
if(dist[n] == 0x3f3f3f3f)return -1;
else return dist[n];
}
int main(){
scanf("%d%d", &n, &m);
memset(g, 0x3f, sizeof g);
while(m--){
int a, b, c;
cin >> a >> b >> c;
g[a][b] = min(g[a][b], c);
}
cout << dijkstra() << endl;
return 0;
}