POJ——T 3687 Labeling Balls

http://poj.org/problem?id=3687

Time Limit: 1000MS		Memory Limit: 65536K
Total Submissions: 14842		Accepted: 4349

Description

Windy has N balls of distinct weights from 1 unit to N units. Now he tries to label them with 1 to N in such a way that:

1. No two balls share the same label.
2. The labeling satisfies several constrains like "The ball labeled with a is lighter than the one labeled with b".

Can you help windy to find a solution?

Input

The first line of input is the number of test case. The first line of each test case contains two integers, N (1 ≤ N ≤ 200) and M (0 ≤ M ≤ 40,000). The next M line each contain two integers a and b indicating the ball labeled with a must be lighter than the one labeled with b. (1 ≤ a, b ≤ N) There is a blank line before each test case.

Output

For each test case output on a single line the balls' weights from label 1 to label N. If several solutions exist, you should output the one with the smallest weight for label 1, then with the smallest weight for label 2, then with the smallest weight for label 3 and so on... If no solution exists, output -1 instead.

Sample Input

5

4 0

4 1
1 1

4 2
1 2
2 1

4 1
2 1

4 1
3 2

Sample Output

1 2 3 4
-1
-1
2 1 3 4
1 3 2 4

Source

POJ Founder Monthly Contest – 2008.08.31, windy7926778

 

啊啊啊，输出重量，Word_day

反向建边大根堆维护，先给重的赋值重量。

 #include <algorithm>
 #include <cstring>
 #include <cstdio>
 #include <queue>

 using namespace std;

 const int M();
 const int N();
 int head[N],sumedge;
 struct Edge
 {
     int v,next;
     Edge(int v=,int next=):v(v),next(next){}
 }edge[M];
 inline void ins(int u,int v)
 {
     edge[++sumedge]=Edge(v,head[u]);
     head[u]=sumedge;
 }

 priority_queue<int>que;
 int rd[N],ans[N],cnt;
 inline void init()
 {
     sumedge=cnt=;
     memset(rd,,sizeof(rd));
     memset(ans,,sizeof(ans));
     memset(head,,sizeof(head));
     memset(edge,,sizeof(edge));
 }

 int AC()
 {
     int t; scanf("%d",&t);
     for(int n,m,if_;t--;init())
     {
         scanf("%d%d",&n,&m);
         for(int u,v;m--;ins(v,u))
             scanf("%d%d",&u,&v),rd[u]++;
         for(int i=;i<=n;i++)
             if(!rd[i]) que.push(i);
         for(int u,v,weight=n;!que.empty();)
         {
             u=que.top(); que.pop();
             ans[u]=weight--;cnt++;
             for(int i=head[u];i;i=edge[i].next)
             {
                 v=edge[i].v;
                 if(--rd[v]==) que.push(v);
             }
         }
         if(cnt!=n) puts("-1");
         else
         {
             for(int i=;i<n;i++)
                 printf("%d ",ans[i]);
             printf("%d\n",ans[cnt]);
         }
     }
     return ;
 }

 int I_want_AC=AC();
 int main(){;}