hdu 1285 确定比赛名次

 1 #include <stdio.h>
 2 #include <string.h>
 3 #include <math.h>
 4 #include <algorithm>
 5 #include <iostream>
 6 #include <ctype.h>
 7 #include <iomanip>
 8 #include <queue>
 9 #include <stdlib.h>
10 using namespace std;
11 
12 #define M 550
13 
14 int du[M],tp[M][M];
15 int n,m,i,j;
16 
17 void topu()
18 {
19     priority_queue<int,vector<int>,greater<int> > Q; //保证小值int先出队列  
20     for(i=1;i<=n;i++){
21         if(du[i]==0)
22             Q.push(i);
23     }
24     bool flag=0;
25     while(!Q.empty()){
26         int ans=Q.top();
27         Q.pop();
28         if(!flag){
29             printf("%d",ans);
30             flag=1;
31         }
32         else{
33             printf(" %d",ans);
34         }
35         for(i=1;i<=n;i++){
36             if(tp[ans][i]){
37                 du[i]--;
38                 if(du[i]==0)
39                     Q.push(i);
40             }
41         }
42     }
43     printf("\n");
44 }
45 
46 int main()
47 {
48     int x,y;
49     while(~scanf("%d%d",&n,&m)){
50         memset(du,0,sizeof(du));
51         memset(tp,0,sizeof(tp));
52         for(i=0;i<m;i++){
53             scanf("%d%d",&x,&y);
54             if(!tp[x][y]){
55                 tp[x][y]=1;
56                 du[y]++;
57             }
58         }
59         topu();
60     }
61 }