Given a non-negative integer num rePResented as a string, remove k digits from the number so that the new number is the smallest possible.
Note: The length of num is less than 10002 and will be ≥ k. The given num does not contain any leading zero. Example 1:
Input: num = “1432219”, k = 3 Output: “1219” Explanation: Remove the three digits 4, 3, and 2 to form the new number 1219 which is the smallest. Example 2:
Input: num = “10200”, k = 1 Output: “200” Explanation: Remove the leading 1 and the number is 200. Note that the output must not contain leading zeroes. Example 3:
Input: num = “10”, k = 2 Output: “0” Explanation: Remove all the digits from the number and it is left with nothing which is 0.
public class Solution { public String removeKdigits(String num, int k) { int len = num.length() - k; char[] chars = new char[num.length()]; int idx = 0; for (int i = 0; i < num.length(); i++) { char c = num.charAt(i); while (idx > 0 && c < chars[idx-1] && k > 0) { idx--; k--; } chars[idx++] = c; } int index = 0; while(index < len && chars[index] == '0') index++; return index == len ? "0" : new String(chars, index, len-index); }}新闻热点
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