Non-Decreasing Array Problem
Description
LeetCode Problem 665.
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:
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Input: nums = [4,2,3]
Output: true
Explanation: You could modify the first 4 to 1 to get a non-decreasing array.
Example 2:
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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
Sample C++ Code
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class Solution {
public:
bool checkPossibility(vector<int>& nums) {
for (int i = 0; i < nums.size() - 1; i++) {
if (nums[i] > nums[i + 1]) {
if (i - 1 >= 0 && nums[i - 1] > nums[i + 1])
nums[i + 1] = nums[i];
else
nums[i] = nums[i + 1];
break;
}
}
for (int i = 0; i < nums.size() - 1; i++) {
if (nums[i] > nums[i + 1])
return false;
}
return true;
}
};