算法训练 操作格子

import java.util.Scanner;

public class Main {
	static int[] number;
	static int[][] op;

	public static void operation(int p, int start, int end) {
		if (p == 1) {
			number[start - 1] = end;
		} else if (p == 2) {
			int sum = 0;
			for (int i = start - 1; i < end; i++)
				sum += number[i];
			System.out.println(sum);
		} else if (p == 3) {
			int max = Integer.MIN_VALUE;
			for (int i = start - 1; i < end; i++)
				if (number[i] > max)
					max = number[i];
			System.out.println(max);
		} 
	}

	public static void main(String[] args) {
		int i = 0, j = 0;
		int n = 0, m = 0;
		Scanner sc = new Scanner(System.in);
		n = sc.nextInt();
		m = sc.nextInt();
		Main.number = new int[n];
		for (i = 0; i < n; i++)
			Main.number[i] = sc.nextInt();
		Main.op = new int[m][];
		for (i = 0; i < m; i++) {
			Main.op[i] = new int[3];
			for (j = 0; j < 3; j++)
				Main.op[i][j] = sc.nextInt();
		}
		for (i = 0; i < m; i++) {
			Main.operation(Main.op[i][0], Main.op[i][1], Main.op[i][2]);
		}
	}
}