题目：
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].
思路：
本题思路如下：
step1:复制数组nums得nums_c
step2:遍历数组，当当前值小于前一个值时，对两个数组做删除操作，nums删除当前值，nums_c删除前面一个值
step3:分别遍历上述两个数组，当两个数组只要有一个符合非递减返回真，否则返回假
代码：
class Solution { public: bool checkPossibility(vector<int>& nums) { vector<int> nums_c = nums; int flag = 0,flag_c=0; for(int i=1;i<nums.size();i++) { if(nums[i]<nums[i-1]) { nums.erase(nums.begin()+i-1); nums_c.erase(nums_c.begin()+i); break; } } if(count==1) { for(int j=1;j<nums.size();j++) { if(nums[j]<nums[j-1]) { flag=1; break; } } for(int j=1;j<nums.size();j++) { if(nums_c[j]<nums_c[j-1]) { flag_c =1; break; } } } if(!flag||!flag_c) return true; else return false; } };
