标签：style blog http color os java io ar for
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.
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.
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.
2 1 1 2 2 2 1 2 2 1
1777 -1
1 #include <iostream> 2 #include <cstdio> 3 #include <cstring> 4 #include <cmath> 5 #include <algorithm> 6 #include <climits> 7 #include <vector> 8 #include <queue> 9 #include <cstdlib> 10 #include <string> 11 #include <set> 12 #include <stack> 13 #define LL long long 14 #define pii pair<int,int> 15 #define INF 0x3f3f3f3f 16 using namespace std; 17 const int maxn = 10010; 18 int n,m,in[maxn],money[maxn]; 19 vector<int>g[maxn]; 20 queue<int>q; 21 int topSort() { 22 int ans = 0; 23 while(!q.empty()) q.pop(); 24 for(int i = 1; i <= n; i++) { 25 if(!in[i]) { 26 q.push(i); 27 money[i] = 888; 28 } 29 } 30 int sum = n; 31 while(!q.empty()){ 32 sum--; 33 int u = q.front(); 34 q.pop(); 35 for(int i = 0; i < g[u].size(); i++){ 36 if(--in[g[u][i]] == 0){ 37 q.push(g[u][i]); 38 money[g[u][i]] = money[u]+1; 39 } 40 } 41 } 42 if(sum > 0) return -1; 43 else{ 44 for(int i = 1; i <= n; i++) 45 ans += money[i]; 46 return ans; 47 } 48 } 49 int main() { 50 int i,u,v; 51 while(~scanf("%d %d",&n,&m)) { 52 for(i = 1; i <= n; i++) { 53 g[i].clear(); 54 in[i] = 0; 55 money[i] = 0; 56 } 57 for(i = 0; i < m; i++) { 58 scanf("%d %d",&v,&u); 59 g[u].push_back(v); 60 in[v]++; 61 } 62 printf("%d\n",topSort()); 63 } 64 return 0; 65 }
标签：style blog http color os java io ar for
原文地址：http://www.cnblogs.com/crackpotisback/p/3945261.html
