题目

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define pb push_back
#define fi first
#define se second
#define lson p << 1
#define rson p << 1 | 1
const int maxn = 1e6 + 5, inf = 1e18, maxm = 4e4 + 5, base = 397;
const int mod = 1e9 + 7;
// const __int128 mod = 212370440130137957LL;
const int N = 1e6;
// int a[1005][1005];
int a[maxn], b[maxn];
bool vis[maxn];
int n, m;
string s;

struct Node{
    // int val, id;
    // bool operator<(const Node &u)const{
    //     return val < u.val;
    // }
    int a, b;
    bool operator<(const Node &u)const{
        return b < u.b;
    }
}c[maxn];

int ans[maxn], pre[maxn];

int calc(int x){
    string s = to_string(x);
    auto[pmn, pmx] = minmax_element(s.begin(), s.end());
    return *pmx - *pmn;
}

void solve(){
    int res = 0;
    int k, q;
    int l, r;
    cin >> l >> r;
    int pw = 1;
    res = l;
    for(int i = 1; i <= 19; i++){//得19次，18次就WA
        for(int j = 0; j < 10; j++){
            int x = l / pw * pw + (pw - 1) / 9 * j;
            // cout << x << ' ' << calc(x) << '\n';
            if(x >= l && x <= r && calc(x) < calc(res)){
                res = x;
            }
            x = r / pw * pw + (pw - 1) / 9 * j;
            // cout << x << ' ' << calc(x) << '\n';
            if(x >= l && x <= r && calc(x) < calc(res)){
                res = x;
            }
        }
        pw *= 10;
    }
    cout << res << '\n';
    /*
    l:1111999
    r:1112200

    对于l，按照这个算法（答案是l或r的前缀拼接上k个相同的数字），只会算到x = 1112222，但是比r大了，无效
    显然1112111是更优的，这个算法不能通过l得到1112111，但是能通过r得到
    */
}   
    
signed main(){
    ios::sync_with_stdio(0);
    cin.tie(0);
    
    int T = 1;
    cin >> T;
    while (T--)
    {
        solve();
    }
    return 0;
}