2024-04-11 10:44:41 +0000 UTC

func removeKdigits(num string, k int) string {
	res := make([]rune, 0)
    
	for _, c := range num {
		for len(res) > 0 && res[len(res) - 1] > c && k > 0 {
			res = res[:len(res) - 1]
			k--
		}

		if len(res) > 0 || c != '0' {
			res = append(res, c)
		}
	}

	for len(res) > 0 && k > 0 {
		res = res[:len(res) - 1]
		k--
	}

	if len(res) == 0 {
		return "0"
	}
	return string(res)
}