HDU 3488 Tour (minimum fee stream for network streams)

Address: hdu3488

This question is basically the same as the question .... Click here for details.

In addition, I think it is necessary to change the code style .. I finally learned why the variable names of the Code are named so long .. I decided to change the source and sink points to source and sink .. S and t are too prone to conflicts... So a simple question has been debugged to the present .. Sad...

The Code is as follows:

#include <iostream>#include <stdio.h>#include <string.h>#include <stdlib.h>#include <math.h>#include <ctype.h>#include <queue>#include <map>#include <algorithm>using namespace std;const int INF=0x3f3f3f3f;int head[500], source, sink, cnt, flow, cost;int d[500], pre[500], q[1000000], cur[500], vis[500];struct node{    int u, v, cap, cost, next;}edge[1000000];void add(int u, int v, int cap, int cost){    edge[cnt].v=v;    edge[cnt].cap=cap;    edge[cnt].cost=cost;    edge[cnt].next=head[u];    head[u]=cnt++;    edge[cnt].v=u;    edge[cnt].cap=0;    edge[cnt].cost=-cost;    edge[cnt].next=head[v];    head[v]=cnt++;}int spfa(){    memset(d,INF,sizeof(d));    memset(vis,0,sizeof(vis));    int minflow=INF, f1=0, f2=0, i;    q[f1++]=source;    d[source]=0;    cur[source]=-1;    while(f1>=f2)    {        int u=q[f2++];        vis[u]=0;        for(i=head[u];i!=-1;i=edge[i].next)        {            int v=edge[i].v;            if(d[v]>d[u]+edge[i].cost&&edge[i].cap)            {                d[v]=d[u]+edge[i].cost;                if(minflow>edge[i].cap)                {                    minflow=edge[i].cap;                }                cur[v]=i;                if(!vis[v])                {                    q[f1++]=v;                    vis[v]=1;                }            }        }    }    if(d[sink]==INF) return 0;    flow+=minflow;    cost+=minflow*d[sink];    for(i=cur[sink];i!=-1;i=cur[edge[i^1].v])    {        edge[i].cap-=minflow;        edge[i^1].cap+=minflow;    }    return 1;}int main(){    int T, n, m, i, j, a, b, c;    scanf("%d",&T);    while(T--)    {        scanf("%d%d",&n,&m);        memset(head,-1,sizeof(head));        cnt=0;        source=0;        sink=2*n+1;        flow=0;        cost=0;        for(i=1;i<=n;i++)        {            add(source,i,1,0);            add(i+n,sink,1,0);        }        while(m--)        {            scanf("%d%d%d",&a,&b,&c);            add(a,b+n,1,c);        }        while(spfa());            printf("%d\n",cost);    }    return 0;}