【图论】单源点最短路模板（有向图）Dijkstra

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#include <cstdio>#include <iostream>#include <cstring>#include <queue>#include <algorithm>#include <vector>using namespace std;const int MAXN = 500;const int MAXM = 20000;typedef pair<int, int> pii;priority_queue<pii, vector<pii>, greater<pii> > que;int dis[MAXN+10], Fa[MAXN+10];bool vis[MAXN+10];struct node{    int v, w;    node *next;}Edges[MAXM*2+10], *ecnt=Edges, *adj[MAXN+10];char ch;void Read(int &u){    while((ch = getchar()) , ch != EOF){        if(ch >= '0' && ch <= '9'){            u = ch - '0';            while((ch = getchar()), ch >= '0' && ch <= '9')                u = u * 10 + ch - '0';            ungetc(ch, stdin);            return;        }    }}void addedge(int u, int v, int w){    ++ecnt;    ecnt->v = v;    ecnt->next = adj[u];    ecnt->w = w;    adj[u] = ecnt;}int main(){    int n, m, u, v, w, s, t;    Read(n); Read(m);    for(int i=1;i<=m;i++){        Read(u); Read(v); Read(w);        addedge(v, u, w);    }    Read(s); Read(t);    que.push(make_pair(0, t));    memset(dis, 0x7f, sizeof dis);    dis[t] = 0;    pii tp;    while(!que.empty()){        tp = que.top(); que.pop();        if(vis[tp.second]) continue;        for(node *p=adj[tp.second];p;p=p->next){            if(dis[p->v] > tp.first + p->w){                dis[p->v] = tp.first + p->w;                Fa[p->v] = tp.second;                que.push(make_pair(dis[p->v], p->v));            }else if(dis[p->v] == tp.first + p->w)                Fa[p->v] = Fa[p->v] ? min(tp.second, Fa[p->v]) : tp.second;        }        vis[tp.second] = true;    }    printf("%d\n%d", dis[s], s);    u = s;    do{        u = Fa[u];        if(u > 0) printf(" %d", u);    }while(u != t);    return 0;}
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