[赛码-字节跳动]dfs

字典序列，但是仅仅通过80%的样例

#include <iostream>
#include <cstring>
#include <cstdio>
#include <vector>
#include <algorithm>
using namespace std;
#define ll long long
class Solution{
    public:
    ll num = 0,cur = 0;
    void lexicalOrder_sub(ll n, ll m,ll temp){
        if(num == m or temp > n)
            return ;
        num += 1;
        cur = temp;
        for(ll i = (ll)0; i < (ll)10; i += (ll)1){
            if(temp * (ll)10 + i <= n)
                lexicalOrder_sub(n, m, temp * (ll)10 + i);            
            else
                break;
        }
    }
    ll lexicalOrder(ll n, ll m){
        for(ll j = (ll)1;j < (ll)10;j += (ll)1){
            if(num >= m)
                break;
            lexicalOrder_sub(n, m, j);
        }
        return cur;
    }
};
int main(){
    ll n,m;
    cin>>n>>m;
    Solution s = Solution();
    cout<<s.lexicalOrder(n,m)<<endl;
    return 0;
}