func_code_string: #include <bits/stdc++.h>   using namespace std;   const int maxn = 310;   const int mod = 1e9 + 7;   long long C[maxn][maxn], Fact[maxn];   void init() {     C[0][0] = 1, Fact[0] = 1;     for (int i = 1; i < maxn; i++) {       C[i][0] = 1, Fact[i] = Fact[i - 1] * i % mod;       for (int j = 1; j <= i; j++)         C[i][j] = (C[i - 1][j - 1] + C[i - 1][j]) % mod;     }   }   long long num[maxn], emp[maxn], dp[maxn][maxn];   int main() {     init();     int n;     scanf( %d , &n);     int tot = 0;     for (int i = 1; i <= n; i++) {       long long tmp;       scanf( %lld , &tmp);       int key = 1;       for (int j = 1; j <= tot; j++) {         long long x = (sqrt(tmp * emp[j]) + 0.5);         if (x * x == tmp * emp[j]) key = 0, num[j]++;       }       if (key) ++tot, num[tot] = 1, emp[tot] = tmp;     }     dp[0][0] = 1;     int m = 0;     for (int i = 1; i <= tot; i++) {       for (int j = 0; j <= n - 1 && j <= m + 1; j++) {         if (dp[i - 1][j] == 0) continue;         for (int k = 1; k <= num[i]; k++) {           long long tmp = dp[i - 1][j] * C[num[i] - 1][k - 1] % mod;           for (int p = 0; p <= k && p <= j + num[i] - k; p++) {             long long temp = tmp * C[j][p] % mod;             dp[i][j + num[i] - k - p] =                 (dp[i][j + num[i] - k - p] + temp * C[m + 1 - j][k - p] % mod) %                 mod;           }         }       }       m += num[i];     }     long long ans = dp[tot][0];     for (int i = 1; i <= tot; i++) ans = ans * Fact[num[i]] % mod;     printf( %lld n , ans);     return 0;   }   