UVa 11491 - Erasing and Winning

// UVa 11491 - Erasing and Winning

#include <stdio.h>
#include <list>
using namespace std;

int main() {
	int digit_count, to_delete;
	scanf("%d %d\n", &digit_count, &to_delete);

	while (digit_count || to_delete) {
		list<char> digits;
		digits.push_back('9' + 1);
		for (int i = 0; i < digit_count; i++) {
			char ch;
			scanf("%c", &ch);
			digits.push_back(ch);
		}
		digits.push_back('0' - 1);

		std::list<char>::iterator it1 = digits.begin(), it2 = it1;
		it2++;
		while (it2 != digits.end() && to_delete > 0) {
			while (*it1 < *it2 && to_delete > 0) {
				it1 = digits.erase(it1);
				it1--;
				to_delete--;
			}
			it1++;
			it2++;
		}
		while (to_delete) {
			digits.pop_back();
			to_delete--;
		}

		digits.pop_front();
		digits.pop_back();
		for (it1 = digits.begin(); it1 != digits.end(); ++it1)
			printf("%c", *it1);
		printf("\n");

		scanf("\n%d %d\n", &digit_count, &to_delete);
	}

	return 0;
}