题目链接：http://acm.hdu.edu.cn/showproblem.php?pid=3183

思路：比较前后两个相邻的字符，如果前面一个字符大于后面一个字符，就把它去掉。

#include <iostream>

#include <cstdio>

#include <cstring>

#include <algorithm>

#include <string>

#include <vector>

#define REP(i, a, b) for (int i = (a); i < (b); ++i)

#define FOR(i, a, b) for (int i = (a); i <= (b): ++i)

using namespace std;

const int MAX_N = (1000 + 100);

int N, M, len;

char str[MAX_N], ans[MAX_N];

int main()

{

	while (cin >> str >> M) {

		N = strlen(str), len = 0;

		REP(i, 0, N - 1) {

			if (str[i] > str[i + 1] && M) {

				--M;

				while (len - 1 >= 0 && ans[len - 1] > str[i + 1] && M) {

					--len, --M;

				}

			}

			else

				ans[len++] = str[i];

		}

		ans[len++] = str[N - 1];

		string tmp = "";

		REP(i, 0, len - M) tmp += ans[i];

		int p = 0;

		N = (int)tmp.size(), len = 0;

		while (p < N && tmp[p] == '0')++p;

		while (p < N) ans[len++] = tmp[p], ++p;

		ans[len] = 0;

		if (strlen(ans) == 0) {

			cout << 0 << endl;

		}

		else

			cout << ans << endl;

	}

	return 0;

}