STL next_permutation(a,a+n) 生成一个序列的全排列。满足可重集。

/**
题目：
链接：
题意：
思路：

*/

#include <iostream>
#include <cstdio>
#include <vector>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
typedef long long LL;
const int mod=1e9+7;
const int maxn=1e2+5;
const double eps = 1e-12;
int main()
{
int a[5] = {0,1,2,2,3};
int n = 5;
sort(a,a+n);
int cnt = 0;
do{
for(int i = 0; i < n; i++){
printf("%d%s",a[i],i==n-1?"\n":" ");
}
cnt++;

}while(next_permutation(a,a+n));
cout<<"num = "<<cnt<<endl;/// 5!/2! = 3*4*5 = 60;
return 0;
}