#include <bits/stdc++.h> using namespace std; const int N = 25; int b[N] , t[N] , x; long long dp[ (1 << 20) + 7][N] , ans; bool can[N][N]; int cnt( int x , int k ) { int res = 0; while( x > 0 ) { res += ( x % k == 1 ); x /= k; } return res; } main() { int n , x; cin >> n; for(int i = 0; i < n; i++) { cin >> x; b[i] = cnt( x , 2 ); t[i] = cnt( x , 3 ); } for(int i = 0; i < n; i++) for(int j = 0; j < n; j++) if( b[i] == b[j] || t[i] == t[j] ) can[i][j] = can[j][i] = 1; for(int i = 0; i < n; i++) dp[ (1 << i) ][i] = 1; for(int mask = 1; mask < (1 << n) - 1; mask++) { for(int last = 0; last < n; last++) { if( mask & ( 1 << last ) == 0 )continue; for(int nxt = 0; nxt < n; nxt++) { if( mask & ( 1 << nxt ) || can[last][nxt] == false ) continue; dp[ mask + ( 1 << nxt ) ][nxt] += dp[mask][last]; } } } for(int i = 0; i < n; i++) { for(int j = 0; j < n; j++) { } } for(int i = 0; i < n; i++) ans += dp[ (1 << n) - 1 ][i]; cout << ans; }

beauty.cpp:23:6: warning: ISO C++ forbids declaration of 'main' with no type [-Wreturn-type]
 main()
      ^
beauty.cpp: In function 'int main()':
beauty.cpp:48:30: warning: suggest parentheses around comparison in operand of '&' [-Wparentheses]
     if( mask & ( 1 << last ) == 0 )continue;
                ~~~~~~~~~~~~~~^~~~