2340单点修改、区间查询

2340单点修改、区间查询

⭐️难度：中等
🌟考点：线段树
📖

📚

import java.util.Scanner;

public class Main {
    static int N = 100010;
    static int n;
    static int[] c = new int[N];
    static int lowbit(int x){ // 求loubit
        return x & -x;
    }
    static void add(int x,int v){ // 单点修改
        for (int i = x; i <= n ; i+=lowbit(i)) {
            c[i] += v;
        }
    }
    static int sum(int x){ // 区间查询
        int res = 0 ;
        for(int i = x;i > 0;i-=lowbit(i)){
            res += c[i];
        }
        return res;
    }

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        n = sc.nextInt();

        for (int i = 1; i <= n; i++) {
            add(i,sc.nextInt()); // 初始化直接调用单点修改
        }

        int m = sc.nextInt();
        while(m-->0){
            int t = sc.nextInt();
            if(t == 1){ // 单点修改
                int x = sc.nextInt();
                int a = sc.nextInt();
                add(x,a);
            }else if(t == 2){  // 区间查询
                int l = sc.nextInt();
                int r = sc.nextInt();
                System.out.println(sum(r) - sum(l - 1)); // 差分求和
            }
        }
    }
}