1 //hdu 1285 2 3 #include<stdio.h> 4 #include<string.h> 5 #include<stack> 6 using namespace std; 7 int map[600][600],n,count[600],seq[600],ff; 8 int topo() 9 { 10 int i,j; 11 ff=0; 12 while(ff<n)//当为排完 13 { 14 for(i=1;i<=n;i++)//从小开始找 15 { 16 if(count[i]==0)//入读为0 17 { 18 count[i]--; 19 seq[ff++]=i; 20 for(j=1;j<=n;j++)//相关的点减度 21 if(map[i][j]) 22 { 23 count[j]--; 24 } 25 26 break; 27 } 28 } 29 } 30 return 1; 31 } 32 int main() 33 { 34 int i,j,m; 35 while(scanf("%d%d",&n,&m)!=EOF) 36 { 37 ff=0; 38 memset(count,0,sizeof(count)); 39 memset(map,0,sizeof(map)); 40 for(i=0;i<m;i++) 41 { 42 int x,y; 43 scanf("%d%d",&x,&y); 44 if(map[x][y]==0)//重边 45 { 46 map[x][y]=1; 47 count[y]++;//入读 48 } 49 } 50 int ans=topo(); 51 if(ans) 52 { 53 for(i=0;i<ff;i++) 54 if(i==0)printf("%d",seq[i]); 55 else printf(" %d",seq[i]); 56 printf(" "); 57 } 58 } 59 } 60 61 62 63 64 /*模版 65 #include<stdio.h> 66 #include<string.h> 67 int map[103][103],n,m; 68 int c[103]; 69 int dfs(int u) 70 { 71 int i,j,l; 72 c[u]=-1; 73 for(i=0;i<n;i++) 74 if(map[u][i]) 75 { 76 if(c[i]<0) 77 return 0; 78 else if(!c[i]&&!dfs(i)) 79 return 0; 80 } 81 c[u]=1; 82 return 1; 83 } 84 int topo() 85 { 86 int i,j; 87 memset(c,0,sizeof(c)); 88 for(i=0;i<n;i++) 89 { 90 if(!c[i]) 91 if(!dfs(i)) 92 return 0; 93 } 94 return 1; 95 } 96 int main() 97 { 98 int i,j,l; 99 while(scanf("%d%d",&n,&m)!=EOF) 100 { 101 memset(map,0,sizeof(map)); 102 if(!n) 103 break; 104 for(i=0;i<m;i++) 105 { 106 int a,b; 107 scanf("%d%d",&a,&b); 108 map[a][b]=1; 109 } 110 if(!topo()) 111 printf("NO "); 112 else printf("YES "); 113 } 114 }*/