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:

Given:    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 ]

 vector<int> getModifiedArray(int length, vector<vector<int>>& updates) {        vector<int> ret(length, 0);        for (int i = 0; i < updates.size(); i++) {            ret[updates[i][0]] += updates[i][2];            int endIdx = updates[i][1] + 1;            if (endIdx < length)                ret[endIdx] -= updates[i][2];        }        for (int i = 1; i < length; i++) {            ret[i] += ret[i - 1];        }        return ret;    }

370. Range Addition