time limit per test
2 seconds
memory limit per test
256 megabytes
You have a positive number of length nn and one additional digit.
You can insert this digit anywhere in the number, including at the beginning or at the end.
Your task is to make the result as large as possible.
For example, you have the number 7654376543, and the additional digit is 44. Then the maximum number you can get is 765443765443, and it can be obtained in two ways — by inserting a digit after the 33th or after the 44th digit of the number.
Input
The first line contains a single integer tt (1≤t≤1041≤t≤104) — the number of test cases.
The descriptions of the test cases follow.
The first line of the description of each test case contains two integers nn and dd (1≤n≤2⋅1051≤n≤2⋅105; 0≤d≤90≤d≤9) — the length of the number and an additional digit, respectively.
The second line of the description of each test case contains a string consisting of nn digits — the number that you have initially. It is guaranteed that the number does not contain leading zeros.
It is guaranteed that the sum of nn for all test cases does not exceed 2⋅1052⋅105.
Output
For each test case, output a string consisting of n+1n+1 digits — the maximum possible number that can be obtained.
Example
Input
Copy
11
5 4
76543
1 0
1
2 5
44
3 6
666
5 6
13579
5 8
97531
19 4
9876543210123456789
5 7
73737
8 1
20000000
7 0
7058959
12 1
828127127732
Output
Copy
765443 10 544 6666 613579 987531 98765443210123456789 773737 210000000 70589590 8281271277321每个测试的时间限制2秒 每个测试的内存限制256兆字节 你有一个长度为n的正数 和一个附加数字。你可以在数字的任何位置插入这个数字，包括开头或结尾。你的任务是使结果尽可能大。例如，你有数字76543 ，附加数字是4 。那么你可以得到的最大数字是765443 ，它可以通过两种方式获得——在数字的第3位或第4位后插入一位数字。输入 第一行包含一个整数t （1≤t≤104 ）——测试用例的数量。测试用例的描述如下。每个测试用例描述的第一行包含两个整数 n 和 d (1≤n≤2⋅105 ; 0≤d≤9 ) — 分别表示数字的长度和附加数字。每个测试用例描述的第二行包含一个由 n 位数字组成的字符串 — 您最初拥有的数字。保证该数字不包含前导零。保证所有测试用例的 n 之和不超过 2⋅105 。输出 对于每个测试用例，输出一个由 n+1 位数字组成的字符串 — 可以获得的最大可能数字。示例 输入副本 11 5 4 76543 1 0 1 2 5 44 3 6 666 5 6 13579 5 8 97531 19 4 9876543210123456789 5 7 73737 8 1 20000000 7 0 7058959 12 1 828127127732 输出副本 765443 10 544 6666 613579 987531 98765443210123456789 773737 210000000 70589590 8281271277321
代码：
#include <iostream>
#include <string>
#include <vector>
using namespace std;void solve() {int t;cin >> t;while (t--) {int n, d;cin >> n >> d;string s;cin >> s;string result;bool inserted = false;for (char c : s) {if (!inserted && d > (c - '0')) {result += (d + '0');inserted = true;}result += c;}if (!inserted) {result += (d + '0');}cout << result << endl;}
}int main() {ios::sync_with_stdio(false);cin.tie(nullptr);solve();return 0;
}