P4163 [SCOI2007]排列——next_permutation

P4163 [SCOI2007]排列

注意要排序；

next_permutation

prev_permutation

#include<cstdio>
#include<cstring>
#include<algorithm>
using namespace std;
const int maxn=;
typedef long long ll;
int T,n,d;
int a[maxn];
char s[maxn];
ll ans;
int main()
{
    scanf("%d",&T);
    while(T--)
    {
        ans=;
        scanf("%s",s);
        scanf("%d",&d);
        int len=strlen(s);
        for(int i=;i<=len;i++) a[i]=s[i-]-'';
        sort(a+,a+len+);
        do
        {
            ll sum=;
            for(int i=;i<=len;i++)
            {
                sum=sum*+a[i];
            }
            if(sum%d==) ans++;
        }while(next_permutation(a+,a+len+));
        printf("%lld\n",ans);
    }

    return ;
}