Difference Arrays

DifferenceArrays.java

package com.blackdragon74;

import java.util.Scanner;

class Solution {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int N = scan.nextInt();
        int M = scan.nextInt();

        long maxSum = 0;

        long[] arr = new long[N + 1];
        while (M-- > 0) {
            int a = scan.nextInt();
            int b = scan.nextInt();
            int k = scan.nextInt();

            arr[a - 1] += k;
            arr[b] -= k;
        }
        scan.close();

        long sum, max;
        sum = max = 0;

        for (long a : arr) {
            sum += a;
            max = Math.max(sum, max);
        }

        System.out.println(max);
    }
}