差分【Java】

https://blog.csdn.net/weixin_45629285/article/details/111146240?ops_request_misc=%257B%2522request%255Fid%2522%253A%2522171084120016800225530603%2522%252C%2522scm%2522%253A%252220140713.130102334…%2522%257D&request_id=171084120016800225530603&biz_id=0&utm_medium=distribute.pc_search_result.none-task-blog-2_alltop_positive~default-1-111146240-null-null.142^v99pc_search_result_base1&utm_term=%E5%B7%AE%E5%88%86&spm=1018.2226.3001.4187

import java.util.Scanner;

public class 差分 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int n =scanner.nextInt();
        int m=scanner.nextInt();
        int [] a = new int[n+10086];
        int [] b= new int[n+10086];
        /**
         * 也就是说，a数组是b数组的前缀和数组，反过来我们把b数组叫做a数组的差分数组。
         * 换句话说，每一个a[i]都是b数组中从头开始的一段区间和。
         */
        for (int i=1;i<=n;i++){
            //构建差分数组
            a[i]=scanner.nextInt();
            b[i]=a[i]-a[i-1];
        }

        int l,r,c=0;
        while (m--!=0){
            l=scanner.nextInt();
            r=scanner.nextInt();
            c=scanner.nextInt();
            //b[l] + c，效果使得a数组中 a[l] 及以后的数都加上了c(红色部分)，
            b[l]+=c;
            //b[r + 1] - c,让a数组中 a[r + 1]及往后的区间再减去c
            b[r+1]-=c;
        }
        for (int i=1;i<=n;i++){
             b[i]+=b[i-1];//求前缀和
            System.out.print(b[i]+" ");
        }
    }
}