差分数组笔记

「力扣」第 370 题：区间加法（会员问题）

参考代码：

import java.util.Arrays;

public class Solution {

    public int[] getModifiedArray(int length, int[][] updates) {
        int[] b = new int[length + 1];
        for (int[] update : updates) {
            int left = update[0];
            int right = update[1];
            int delta = update[2];

            b[left] += delta;
            b[right + 1] -= delta;
        }

        // 只能写 < 不能写 <=
        for (int i = 1; i < length; i++) {
            b[i] += b[i - 1];
        }

        int[] res = new int[length];
        System.arraycopy(b, 0, res, 0, length);
        return res;
    }

    public static void main(String[] args) {
        int length = 5;
        int[][] updates = {{1, 3, 2}, {2, 4, 3}, {0, 2, -2}};
        Solution solution = new Solution();
        int[] res = solution.getModifiedArray(length, updates);
        System.out.println(Arrays.toString(res));
    }
}