质数排列
分别找出质数和合数的数量,将两者的阶乘相乘即可
class Solution {
public int numPrimeArrangements(int n) {
int cnt = 0;
for(int i = 2; i <= n; i++){
boolean flag = true;
for(int j = 2; j*j <= i; j++){
if(i % j == 0){
flag = false;
break;
}
}
if(flag) cnt++;
}
long res = 1, mod = (int)1e9+7;
for(int i = 1; i <= cnt; i++)
res = (res * i) % mod;
for(int i = 1; i <= n-cnt; i++)
res = (res * i) % mod;
return (int)res;
}
}
标签:排列,int,质数,leetcode1175,numPrimeArrangements,阶乘
From: https://www.cnblogs.com/xzh-yyds/p/16592923.html