POJ 2387 - Til the Cows Come Home ( dijkstra求最短路 )

题意

思路

AC代码

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstring>

using namespace std;
const int INF = 0x3f3f3f3f;
const int maxn = 1e3+10;
int cost[maxn][maxn];
bool vis[maxn];
int d[maxn];
int n;

void init(){
memset(d, INF, sizeof(d));
memset(vis, false, sizeof(vis) );
for( int i = 1; i <= n; i++ )
for( int j = 1; j <= n; j++ ){
if( i == j )  cost[i][j] = 0;
else    cost[i][j] = INF;
}
}

void dijkstra(){
d[1] = 0;
for(;;){
int v = -1;
for( int i = 1; i <= n; i++ )
if( !vis[i] && (v == -1 || d[i] < d[v]) )
v = i;
if( v == -1 ) break;
vis[v] = true;
for( int i = 1; i <= n; i++ )
d[i] = min(d[i], d[v] + cost[v][i]);
}
}

int main()
{
int T;
int a, b, c;
while( ~scanf("%d%d",&T, &n) ){
init();
while( T-- ){
scanf("%d%d%d",&a, &b, &c);
if( c < cost[a][b] && c < cost[b][a] ){ //重边
cost[a][b] = c;
cost[b][a] = c;
}
}
dijkstra();
printf("%d\n",d
);
}
return 0;
}