665. Non-decreasing Array

Given an array with n integers, your task is to check if it could become non-decreasing by modifying at most 1 element.

We define an array is non-decreasing if array[i] <= array[i + 1] holds for every i (1 <= i < n).

Example 1:

Input: [4,2,3]
Output: True
Explanation: You could modify the first 4 to 1 to get a non-decreasing array.

Example 2:

Input: [4,2,1]
Output: False
Explanation: You can't get a non-decreasing array by modify at most one element.

Note: The n belongs to [1, 10,000].

给定一个具有N个整型元素的数组，检查该数组是否能够通过最多改变一个元素的值，从而使得其本身变为单调非减数组，我们定义单调非减是指对于数组中的每一个有效下标i,都有 a[i] <= a[i+1]。 

    public boolean checkPossibility(int[] nums) {
        boolean changed = false;
        for (int i = 0; i < nums.length - 1; i++) {
            if (nums[i] > nums[i + 1]) {
                if (!changed) {
                    if (i == 0 || nums[i-1] <= nums[i+1]) {
                        nums[i] = nums[i+1];
                    }else
                    {
                        nums[i+1] = nums[i];
                    }
                    changed = true;
                } else {
                    return false;
                }
            }
        }
        return true;
    }