一、題目

An integer has monotone increasing digits if and only if each pair of adjacent digits x and y satisfy x <= y.

Given an integer n, return the largest number that is less than or equal to n with monotone increasing digits.

Example 1:

Input: n = 10
Output: 9
Example 2:

Input: n = 1234
Output: 1234
Example 3:

Input: n = 332
Output: 299

Constraints:

0 <= n <= 109

二、題解

class Solution {
public:int monotoneIncreasingDigits(int n) {string s = to_string(n);int flag = s.size();for(int i = s.size() - 1;i > 0;i--){if(s[i-1] > s[i]){flag = i;s[i-1]--;}}for(int i = flag;i < s.size();i++){s[i] = '9';}return stoi(s);}
};