STL。

1 /* 1716 */ 2 #include 
     
       3 #include 
      
        4 #include 
       
         5 #include 
        
          6 using namespace std; 7  8 #define MAXN 30 9 int b[MAXN];10 11 int main() {12     int a[4];13     int t = 0, n;14     int i, j, k;15     16     #ifndef ONLINE_JUDGE17         freopen("data.in", "r", stdin);18         freopen("data.out", "w", stdout);19     #endif20     21     while (1) {22         j = 0;23         for (i=0; i<4; ++i) {24             scanf("%d", &a[i]);25             j += a[i];26         }27         if (j == 0)28             break;29         if (t++)30             printf("\n");31         sort(a, a+4);32         n = 0;33         do {34             if (a[0]) {35                 b[n++] = 1000*a[0]+100*a[1]+10*a[2]+a[3];36             }37         } while (next_permutation(a, a+4));38         b[n] = 0;39         for (i=0; i