二维数组求最大子数组

时间：2015-04-09 23:38:52 阅读：174 评论：0 收藏：0 [点我收藏+]

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设计思路：

首先定义产生二维数组，定义可输入二维数组行和列，各位数随机产生；

然后进行最大子数组的求和比较，从每行的第一个数为子数组的起点开始进行不同的子数组遍历比较，只存放最大的子数组，以及记录最大子数组的位置，从第一个数开始每行每列进行求和比较，以求得最大子数组的值，以及最大子数组所包含的数；

最后进行结果的输出与验证。

代码：

法一：

package zishuzu;

import java.util.*;

public class zuixiaozishuzu {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        int m,n,M,N,max,sum;
        int i,i1,i2,j,j1,j2;
        int shouL,shouR,weiL,weiR;
        Scanner sc = new Scanner(System.in);
        System.out.println("输入二维数组的行数和列数：");
        m =    sc.nextInt();
        n = sc.nextInt();
        System.out.println("输入该二位数组的取值范围（保证第一个数小于第二个数）:");
        M = sc.nextInt();    
        N = sc.nextInt(); 
        
        int[][] Shuzu = new int[m][n];
        for(i = 0;i < m;i++)
            for(j = 0;j < n;j++)
            {
                Shuzu[i][j] = N + (int)(Math.random()*(M - N));
            }
        System.out.println("该随机二维数组为：");
        for(i = 0;i < m;i++)
            for(j = 0;j < n;j++)
            {
                System.out.print(Shuzu[i][j]+"\t");
                if(j == n - 1)
                {
                    System.out.print("\n");
                }
            }
        
        sum =0;
        max = Shuzu[0][0];
        shouL = 0;
        shouR = 0;
        weiL = 0;
        weiR = 0;

        for(i = 0;i < m;i++)
        {
            for(j = 0;j < n;j++)
            {
                for(i1 = i;i1 < m;i1++)
                {
                    for(j1 = j;j1 < n;j1++)
                    {
                        for(i2 = i;i2 <= i1;i2++)
                        {
                            for(j2 = j;j2 <= j1;j2++)
                            {
                                sum = sum + Shuzu[i2][j2];
                            }
                        }
                        if(max <= sum)
                        {
                            max = sum;
                            shouL = i;
                            shouR = j;
                            weiL = i1;
                            weiR = j1;
                        }
                        sum = 0;
                    }
                }
            }
        }        
        
        System.out.println("最大子数组和为：");
        System.out.println(max);
        System.out.println("最大子数组为：");
        for(i = shouL;i <= weiL;i++)
            for(j = shouR;j <= weiR;j++)
            {
                System.out.print(Shuzu[i][j] + "\t");
                if(j == weiR)
                {
                    System.out.print("\n");
                }
            }
        
        sc.close();
    }

}法二：
package zishuzu;

import java.util.*;

public class zuixiaozishuzu {

    public static void main(String[] args) {
        // TODO Auto-generated method stub

        int m,n,M,N,max,sum;
        int i,i1,i2,j,j1,j2;
        int shouL,shouR,weiL,weiR;
        Scanner sc = new Scanner(System.in);
        System.out.println("输入二维数组的行数和列数：");
        m =    sc.nextInt();
        n = sc.nextInt();
        System.out.println("输入该二位数组的取值范围（保证第一个数小于第二个数）:");
        M = sc.nextInt();    
        N = sc.nextInt(); 
        
        int[][] Shuzu = new int[m][n];
        for(i = 0;i < m;i++)
            for(j = 0;j < n;j++)
            {
                Shuzu[i][j] = N + (int)(Math.random()*(M - N));
            }
        System.out.println("该随机二维数组为：");
        for(i = 0;i < m;i++)
            for(j = 0;j < n;j++)
            {
                System.out.print(Shuzu[i][j]+"\t");
                if(j == n - 1)
                {
                    System.out.print("\n");
                }
            }
        
        sum =0;
        max = Shuzu[0][0];
        shouL = 0;
        shouR = 0;
        weiL = 0;
        weiR = 0;

        i = 0;
        for(j = 0;j < n;j++)
        {
            i1 = i;
            for(j1 =j;j1 < n;j1++)
            {
                i2 = i;
                for(j2 = j;j2 <= j1;j2++)
                {
                    sum += Shuzu[i2][j2];
                    if((j2 == j1)&&(i2 < i1))
                    {
                        i2++;
                        j2 = j;
                    }
                    else if(j2 == j1&&i2 == i1)
                    {
                        break;
                    }
                }
                if(max < sum)
                {
                    max = sum;
                    shouL = i;
                    shouR = j;
                    weiL = i1;
                    weiR = j1;
                }
                sum = 0;
                if(j1 == n -1 && i1 < m -1)
                {
                    i1++;
                    j1 = j;
                }
                else if(j1 == n-1 && j1 == m - 1)
                {
                    break;
                }
            }
            if(j == n - 1 && j < m - 1)
            {
                i++;
                j = 0;
            }
            else if(j == n - 1 && j == m - 1)
            {
                break;
            }
        }        
        
        System.out.println("最大子数组和为：");
        System.out.println(max);
        System.out.println("最大子数组为：");
        for(i = shouL;i <= weiL;i++)
            for(j = shouR;j <= weiR;j++)
            {
                System.out.print(Shuzu[i][j] + "\t");
                if(j == weiR)
                {
                    System.out.print("\n");
                }
            }
        
        sc.close();
    }

}