POJ 1949 Chores

水题：拓扑排序

View Code

#include <stdio.h>
#include <memory.h>

#define N 10002
#define M 1000000
#define MOV(x) (x=(x+1)%N) 

int needtime[N],finaltime[N],indegree[N];
int queue[N],font,rear;
int nodevp[N];
int nodeu[M],next[M],ind;

void addedge(int v,int u)
{
    nodeu[ind]=u;
    next[ind]=nodevp[v];
    nodevp[v]=ind++;
}

void solve()
{
    int n,i,j,v,u;

    scanf("%d",&n);
    memset(nodevp,-1,sizeof(nodevp));
    for(i=1;i<=n;i++)
    {
        scanf("%d %d",needtime+i,indegree+i);
        if(indegree[i]!=0)
        {
            for(j=0;j<indegree[i];j++)
            {
                scanf("%d",&v);
                addedge(v,i);
            }
        }
        else    queue[MOV(rear)]=i;
    }

    while(font!=rear)
    {
        v=queue[MOV(font)];
        for(i=nodevp[v];~i;i=next[i])
        {
            u=nodeu[i];
            if(--indegree[u] == 0)    queue[MOV(rear)]=u;
            if(finaltime[v]+needtime[v]>finaltime[u])    finaltime[u]=finaltime[v]+needtime[v];
        }
    }

    for(v=0,i=1;i<=n;i++)    
    {
        finaltime[i]+=needtime[i];
        if(finaltime[v]<finaltime[i])    v=i;
    }

    printf("%d\n",finaltime[v]);
}

int main()
{
//    freopen("input.txt","r",stdin);

    solve();

    return 0;
}