POJ

一开始WA，到网上看了看貌似是重边的问题，但题目中的重边不是最新的那一条而是最小的那一条，我的dijkstra无所畏惧，最后看了看原来是输入写反了、、、、、、

#include <cstdio>#include <cstring>#include <iostream>#include <algorithm>#include <vector>#include <queue>using namespace std;typedef pair<int, int> P;const int INF = 0x3f3f3f3f;const int maxn = 2010;int n, m, u, v, cost, d[maxn], vis[maxn];vector<P> g[maxn];void dijkstra() {    for (int i = 1; i <= n; i++) {        d[i] = INF, vis[i] = 0;    }    d[1] = 0;    priority_queue<P, vector<P>, greater<P> > q;    q.push(make_pair(0, 1));    while(!q.empty()) {        u = q.top().second; q.pop();        if(vis[u]) continue;        vis[u] = 1;        for (int i = 0; i < g[u].size(); i++) {            v = g[u][i].first, cost = g[u][i].second;            if (d[v] > d[u] + cost) {                d[v] = d[u] + cost;                q.push(make_pair(d[v], v));            }        }    }}int main() {    while (~scanf("%d %d", &m, &n)) {        for (int i = 1; i <= n; i++) g[i].clear();        for (int i = 1; i <= m; i++) {            scanf("%d %d %d", &u, &v, &cost);            g[u].push_back(make_pair(v, cost));            g[v].push_back(make_pair(u, cost));        }        dijkstra();        printf("%d\n", d[n]);    }    return 0;}