标签：拓扑排序   数据结构   

注意顺序

Reward

2 1
1 2
2 2
1 2
2 1

1777
-1

#include <stdio.h>
#include <stdlib.h>
#include <malloc.h>
#include <limits.h>
#include <ctype.h>
#include <string.h>
#include <string>
#include <math.h>
#include <algorithm>
#include <iostream>
#include <queue>
#include <stack>
#include <deque>
#include <vector>
#include <set>
#include <map>
using namespace std;
#define MAXN 10011
int money[MAXN];
int head[MAXN];
int into[MAXN];

struct node{
    int to;
    int next;
}edge[20010];

int main(){
    int n,m;
    int i,j;

    while(~scanf("%d%d",&n,&m)){
        for(i=1;i<=n;i++){
            money[i] = 888;
        }
        memset(into,0,sizeof(into));
        memset(head,-1,sizeof(head));
        int k = 0;
        while(m--){
            scanf("%d%d",&j,&i);
            edge[k].to = j;
            edge[k].next = head[i];
            head[i] = k++;
            into[j]++;
        }
        queue<int>t;
        for(i=1;i<=n;i++){
            if(into[i] == 0){
                t.push(i);
            }
        }
        int num = 0;
        int ans = 0;
        while(!t.empty()){
            int u = t.front();
            ans+=money[u];
            t.pop();
            num++;
            for(k=head[u];k!=-1;k=edge[k].next){
                if(--into[edge[k].to] == 0){//--的位置注意
                    t.push(edge[k].to);
                    money[edge[k].to] = money[u] + 1;
                }
                //t.push(edge[k].to);
                //money[edge[k].to] = money[u] + 1;
            }
        }
        if(num != n){
            ans = -1;
        }
        printf("%d\n",ans);
    }

    return 0;
}

拓扑排序 HDU 2647

标签：拓扑排序   数据结构   

原文地址：http://blog.csdn.net/zcr_7/article/details/39900091