F1. Nearest Beautiful Number (easy version)

预处理加二分

#include <bits/stdc++.h>
using namespace std;
const int N = 3e5 + 3;
#define int long long
set<int>cun1,cun2;
signed main()
{//单个for (int i=1;i<=9;i++){int res = 0;for (int j=0;j<=9;j++) {res = res*10+i;cun1.insert(res);}}//两个int cou = pow(2,10);for (int i=0;i<=9;i++){for (int j=i+1;j<=9;j++){for(int k =1 ;k <=10 ; k++)//位数{for (int h=0;h<(1<<k);h++){int res = 0;for (int m = k-1;m>=0;m--){if (h>>m&1) res = res*10+i;else res = res*10+j;}cun2.insert(res);}}}}int t;cin >> t;while (t--){int n, k;cin >> n >> k;if (k==1) cout<<*cun1.lower_bound(n)<<endl;else cout<<*cun2.lower_bound(n)<<endl;}
}