RewardTime Limit: 2000/1000 MS (Java/Others)Memory Limit: 32768/32768 K (Java/Others)Total Submission(s): 5636Accepted Submission(s): 1712
Problem Description
Dandelion’s uncle is a boss of a factory. As the spring festival is coming , he wants to distribute rewards to his workers. Now he has a trouble about how to distribute the rewards.The workers will compare their rewards ,and some one may have demands of the distributing of rewards ,just like a’s reward should more than b’s.Dandelion’s unclue wants to fulfill all the demands, of course ,he wants to use the least money.Every work’s reward will be at least 888 , because it’s a lucky number.
Input
One line with two integers n and m ,stands for the number of works and the number of demands .(n<=10000,m<=20000)then m lines ,each line contains two integers a and b ,stands for a’s reward should be more than b’s.
Output
For every case ,print the least money dandelion ‘s uncle needs to distribute .If it’s impossible to fulfill all the works’ demands ,print -1.
Sample Input
2 11 22 21 22 1
Sample Output
1777-1
题意：
老板要给很多员工发奖金，， 但是部分员工有个虚伪心态， 认为自己的奖金必须比某些人高才心理平衡； 但是老板很人道， 想满足所有人的要求， 并且很吝啬，想画的钱最少，问满足所有人的前提下最少花多少钱。
#include <cstdio>#include <cstring>#include <algorithm>#include <queue>#define maxn 11000using namespace std;char map[maxn];int indu[maxn];int head[maxn], cnt;int n, m;int a[maxn];struct node {int u, v, next;};node edge[110000];void init(){cnt = 0;memset(head, -1, sizeof(head));memset(indu, 0, sizeof(indu));for(int i = 1; i <= n; ++i)//所有人的工资一开始都为888a[i] = 888;}void add(int u, int v){edge[cnt] = {u, v, head[u]};head[u] = cnt++;}void input(){while(m–){int a, b;scanf("%d%d", &b, &a);add(a, b);//注意是反向的, wa了一次indu[b]++;}}void topsort(){queue<int >q;int sum = 0;int ans = 0;for(int i = 1; i <= n; ++i){if(!indu[i]){q.push(i);ans++;}}while(!q.empty()){int u = q.front();sum += a[u];q.pop();for(int i = head[u]; i != -1; i = edge[i].next){int v = edge[i].v;indu[v]–;if(!indu[v]){q.push(v);a[v] = a[u] + 1;//保证后一个人的工资比前一个人的工资高ans++;}}}if(ans == n)printf("%d\n", sum);elseprintf("-1\n");}int main (){while(scanf("%d%d", &n, &m) != EOF){init();input();topsort();}return 0;}
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