UESTC 電子科大專題訓練 數論 E
阿新 • • 發佈:2017-07-26
pro code tps sta ems ios net 由於 include
UESTC 1716
題意:中文題
思路:先把男生排列,由於是圓桌,所以每個位置都是一樣的,排列方案為A(n,n)/n,再對女生排列,由於男生已經在座位上了,所以此時每個座位是不一樣的,方案數為A(n,n)
AC代碼:
#include "iostream" #include "string.h" #include "stack" #include "queue" #include "string" #include "vector" #include "set" #include "map" #include "algorithm" #include "stdio.h" #include "math.h" #define ll long long #define bug(x) cout<<x<<" "<<"UUUUU"<<endl; #define mem(a) memset(a,0,sizeof(a)) #define mp(x,y) make_pair(x,y) #define pb(x) push_back(x) using namespace std; const long long INF = 1e18+1LL; const int inf = 1e9+1e8; const int N=1e5+100; const ll mod=1e9+7; ll ans=1; int main(){ ios::sync_with_stdio(false),cin.tie(0),cout.tie(0); int n; cin>>n; for(int i=2; i<n; ++i){ ans*=i*i; } cout<<ans*n<<"\n"; return 0; }
UESTC 電子科大專題訓練 數論 E