AcWing 849. Dijkstra求最短路 I
原题链接
简单
作者:
墨白
,
2021-01-18 21:50:15
,
所有人可见
,
阅读 265
C++ 代码
#include <iostream>
#include <cstring>
#include <algorithm>
using namespace std;
const int N = 510;
int g[N][N];
int dist[N];
bool st[N];
int n,m;
int dijkstra(){
memset(dist,0x3f,sizeof dist);
dist[1] = 0;
for(int i = 0; i < n - 1;++i){
int t = -1;
for(int j = 1;j <= n;++j){
if(!st[j] && (t == -1 || dist[j] < dist[t])){
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;
return dist[n];
}
int main(){
cin >> 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);
}
int res = dijkstra();
cout << res << endl;
return 0;
}