370. Range Addition

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 ] Show Hint

public class Solution {
    public int[] getModifiedArray(int length, int[][] updates) {

        int[] res = new int[length+1];
        for(int i=0; i< updates.length; i++){
            int[] inc = updates[i];
            res[inc[0]] += inc[2];
            res[inc[1] +1] -= inc[2];
        }

        for(int i=1; i<res.length; i++){
            res[i] += res[i-1];
        }

        return Arrays.copyOfRange(res, 0, res.length-1);
    }
}