【HDOJ】3419 The Three Groups

记忆化搜索。

 /* 3419 */
 #include <cstdio>
 #include <cstring>
 #include <cstdlib>

 #define MAXN 10

 int ans;
 int n[];
 int x[];
 bool visit[MAXN];
 int cnt[MAXN][MAXN][MAXN];

 void dfs(int d, int i, int v) {
     if (i == ) {
         if (x[]*x[] == x[])
             ++ans;
         return ;
     }
     if (d < n[i]) {
         for (int j=; j<MAXN; ++j) {
             if (!visit[j]) {
                 visit[j] = true;
                 dfs(d+, i, v*+j);
                 visit[j] = false;
             }
         }
     } else {
         x[i] = v;
         dfs(, i+, );
     }
 }

 int main() {
     int a, b, c;
     int i, j, k;

     #ifndef ONLINE_JUDGE
         freopen("data.in", "r", stdin);
         freopen("data.out", "w", stdout);
     #endif

     memset(cnt, -, sizeof(cnt));
     while (scanf("%d %d %d", &a, &b, &c)!=EOF && (a||b||c)) {
         if (a+b < c) {
             puts("");
         } else if (a>c || b>c){
             puts("");
         } else if (a+b-c>) {
             puts("");
         } else if (cnt[a][b][c] >= ) {
             printf("%d\n", cnt[a][b][c]);
         } else {
             memset(visit, false, sizeof(visit));
             n[] = a;
             n[] = b;
             n[] = c;
             ans = ;
             dfs(, , );
             cnt[a][b][c] = ans;
             printf("%d\n", ans);
         }
     }

     return ;
 }