@TOC

## # 题目描述

Assume you have an array of length `n` initialized with all 0's and are given `k` update operations.

Each operation is represented as a triplet: `[startIndex, endIndex, inc]` which increments each element of subarray `A[startIndex ... endIndex]` (`startIndex` and `endIndex` inclusive) with inc.

Return the modified array after all `k` operations were executed.

Example:

``````Input: length = 5, updates = [[1,3,2],[2,4,3],[0,2,-2]]
Output: [-2,0,3,5,3]
Explanation:

Initial state:
[0,0,0,0,0]

After applying operation [1,3,2]:
[0,2,2,2,0]

After applying operation [2,4,3]:
[0,2,5,5,3]

After applying operation [0,2,-2]:
[-2,0,3,5,3]
``````

## # 解题方法

### # 只修改区间起终点

C++代码如下：

``````class Solution {
public:
vector<int> getModifiedArray(int length, vector<vector<int>>& updates) {
vector<int> res(length, 0);
for (auto& up : updates) {
int start = up[0], end = up[1], inc = up[2];
res[start] += inc;
if (end < length - 1)
res[end + 1] -= inc;
}
int cursum = 0;
for (int i = 0; i < length; ++i) {
cursum += res[i];
res[i] = cursum;
}
return res;
}
};
``````

## # 日期

2019 年 9 月 18 日 —— 今日又是九一八