Java算法之矩阵中子矩阵最大累加和

Posted 2021-07-21 笔触狂放

题目:矩阵中子矩阵最大累加和

答案:

package com.student;

import java.util.Arrays;
import java.util.Random;
import java.util.Scanner;

public class T4_6 {
	
	private int[][] nums=null;
	
	private void init() {
		System.out.println("请输入二维数组的阶数:");
		Scanner scanner=new Scanner(System.in);
		int n=scanner.nextInt();
		scanner.close();
		
		nums=new int[n][n];
		for (int i = 0; i < nums.length; i++) {
			for (int j = 0; j < nums[i].length; j++) {
				nums[i][j]=Math.random()>0.3?new Random().nextInt(10):new Random().nextInt(10)*(-1);
				System.out.print(nums[i][j]+"\\t");
			}
			System.out.println();
		}
		print();
	}
	
	private void print() {
		int[] nn=new int[nums.length];
		int max=0;
		int row=0;
		while (row<nums.length) {
			for (int i = row; i < nn.length; i++) {
				for (int j = 0; j < nn.length; j++) {
					nn[j]+=nums[i][j];
				}
				//把临时的一维数组找出最大累加和
				int a=print(nn);
				if (a>max) {
					max=a;
				}
			}
			//清空临时的一维数组
			Arrays.fill(nn, 0);
			row++;
		}
		System.out.println("最大的累加和为:"+max);
	}
	
	private int print(int[] x) {
		int max=x[0];
		int sum=max;
		//定义两个变量，保存开始累加的下标，结束累加的下标
		int left=0,right=0;
		for (int i = 1; i < x.length; i++) {
			if (sum>0) {
				sum+=x[i];
			}else {
				sum=x[i];
				left=i;
			}
			
			if (sum>max) {
				max=sum;
				right=i;
			}
		}
		
		return max;
		
	}

	public static void main(String[] args) {
		new T4_6().init();
	}

}