https://leetcode.com/problems/non-decreasing-array/
Given an array nums with n integers, your task is to check if it could become non-decreasing by modifying at most one element. We define an array is non-decreasing if nums[i] <= nums[i + 1] holds for every i (0-based) such that (0 <= i <= n - 2).
Example 1: Input: nums = [4,2,3] Output: true Explanation: You could modify the first 4 to 1 to get a non-decreasing array. Example 2: Input: nums = [4,2,1] Output: false Explanation: You can’t get a non-decreasing array by modify at most one element.
Constraints:
n == nums.length
1 <= n <= 10^4
-10^5 <= nums[i] <= 10^5
- code
class Solution {
public boolean checkPossibility(int[] nums) {
int ct = 0;
for (int i = 1; i < nums.length; i++) {
if (nums[i - 1] > nums[i]) {
if (ct == 0) {
if (i == 1 || (i - 2 >= 0 && nums[i] >= nums[i - 2])) {
nums[i - 1] = nums[i];
} else {
nums[i] = nums[i - 1];
}
ct++;
} else {
return false;
}
}
}
return true;
}
}