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  • BZOJ 1922 大陆争霸

    有点迷,spfa好像不好写,必须dijkstra

    #include<iostream>
    #include<cstdio>
    #include<cstring>
    #include<algorithm>
    #include<queue>
    #define maxv 3050
    #define maxe 70050
    using namespace std;
    int n,m,x,y,z,l,cnt[maxv],con[maxv][maxv],d1[maxv],d2[maxv],g[maxv],nume=1;
    struct pnt
    {
        int v,val;
        pnt (int v,int val):v(v),val(val) {}
        pnt () {}
        friend bool operator < (const pnt &x,const pnt &y)
        {
            return x.val>y.val;
        }
    }p[maxv];
    priority_queue <pnt> q;
    bool vis[maxv];
    struct edge
    {
        int v,w,nxt;
    }e[maxe];
    void addedge(int u,int v,int w)
    {
        e[++nume].v=v;e[nume].w=w;
        e[nume].nxt=g[u];g[u]=nume;
    }
    void dijkstra()
    {
        q.push(pnt(1,0));
        for (int i=2;i<=n;i++) d1[i]=1000000000;
        while (!q.empty())
        {
            pnt head=q.top();q.pop();
            if (vis[head.v]) continue;vis[head.v]=true;
            for (int i=g[head.v];i;i=e[i].nxt)
            {
                int v=e[i].v;
                if (d1[v]>max(d1[head.v],d2[head.v])+e[i].w)
                {
                    d1[v]=max(d1[head.v],d2[head.v])+e[i].w;
                    if (!cnt[v]) q.push(pnt(v,max(d1[v],d2[v])));
                }
            }
            for (int i=1;i<=con[head.v][0];i++)
            {
                int v=con[head.v][i];
                cnt[v]--;d2[v]=max(d2[v],max(d1[head.v],d2[head.v]));
                if (!cnt[v]) q.push(pnt(v,max(d1[v],d2[v])));
            }
        }
    }
    int main()
    {
        scanf("%d%d",&n,&m);
        for (int i=1;i<=m;i++)
        {
            scanf("%d%d%d",&x,&y,&z);
            if (x!=y) addedge(x,y,z);
        }
        for (int i=1;i<=n;i++)
        {
            scanf("%d",&cnt[i]);
            for (int j=1;j<=cnt[i];j++)
            {
                scanf("%d",&x);
                con[x][++con[x][0]]=i;
            }
        }
        dijkstra();
        printf("%d
    ",max(d1[n],d2[n]));
        return 0;
    
    }
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  • 原文地址:https://www.cnblogs.com/ziliuziliu/p/7635831.html
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