topic:
Here is an integer array of length n. Please judge whether the array can be turned into a non-decreasing sequence when one element is changed at most.
We define a non-decreasing sequence like this: For any i (0 <= i <= n-2) in the array, nums[i] <= nums[i + 1] is always satisfied.
Example 1:
Input: nums = [4,2,3]
Output: true
Explanation: You can make it a non-decreasing sequence by changing the first 4 to 1.
Example 2:Input: nums = [4,2,1]
Output: false
Explanation: You cannot change one element to a non-decreasing sequence.
Code:
/**
* @param {number[]} nums
* @return {boolean}
*/
var checkPossibility = function (nums) {
const n = nums.length;
let cnt = 0;
for (let i = 0; i < n - 1; ++i) {
const x = nums[i], y = nums[i + 1];
if (x > y) {
cnt++;
if (cnt > 1) {
return false;
}
if (i > 0 && y < nums[i - 1]) {
nums[i + 1] = x;
}
}
}
return true;
};operation result:
