蓝桥杯 带分数(DFS)

#include <stdio.h>
#include <iostream>
#include <string.h>
#include <algorithm>
using namespace std;

int flag1[20],flag2[20],n;
int l,v,ls,ans;

int check_l(int ln)
{
    int len = 0;
    while(ln)
    {
        int r = ln%10;
        if(flag1[r])return 0;
        flag1[r] = 1;
        ln/=10;
        len++;
    }
    ls = 9-len;
    return 1;
}

int judge(int ln)
{
    int len = 0;
    memcpy(flag2,flag1,sizeof(flag2));
    while(ln)
    {
        int r = ln%10;
        if(flag2[r])return 0;
        flag2[r] = 1;
        ln/=10;
        len++;
    }
    return len;
}

void dfs(int len,int x)
{
    if(len <= ls/2)
    {
        if(judge(v*x)==ls-len)
            ans++;
        for(int i = 1; i<10; i++)
        {
            if(flag1[i])continue;
            flag1[i] = 1;
            dfs(len+1,x*10+i);
            flag1[i] = 0;
        }
    }
}

int main()
{
    cin >> n;
    ans = 0;
    for(l = 1; l<n; l++)
    {
        flag1[0] = 1;
        if(check_l(l))
        {
            v = n-l;
            dfs(0,0);
        }
        memset(flag1,0,sizeof(flag1));
    }
    cout << ans << endl;

    return 0;
}