最大累加矩阵大小

package com.hzins.suanfa;

public class MaxSum {
    public static int function(int[] array) {
        int cur = array[0];
        int max = array[0];
        for (int i = 1; i < array.length; i++) {
            cur = cur < 0 ? 0 : cur;
            cur += array[i];
            max = Math.max(max, cur);
        }
        return max;
    }
    /**
     * O(n^3)
     * @param array
     * @return
     */
    public static int maxMatrixSum(int[][] array) {
        int max = 0;
        int[] sumArray = null;
        int sumArrayLength = array[0].length;
        //前两个for作用 第一行到第五行 第二行到第五行 。。。。。 从上到下累加成一维数组
        for (int i = 0; i < array.length; i++) {
            sumArray = new int[sumArrayLength];
            for (int j = i; j < array.length; j++) {
                int cur = 0;
                //开始变成子数组中最大累加和问题 每一个这个问题需要一个全新的cur
                for (int k = 0; k < sumArrayLength; k++) {
                    cur = cur < 0 ? 0 : cur;
                    sumArray[k] += array[j][k];
                    cur += sumArray[k];
                    max = Math.max(cur, max);
                }
            }
        }
        return max;
    }

    public static void main(String[] args) {
        int[][] a = new int[3][5];
        for(int i = 0;i < a.length;i ++){
            a[i][0] = 3;
            a[i][1] = -4;
            a[i][2] = 7;
            a[i][3] = -4;
            a[i][4] = 2;
        }
        for(int i = 0;i< a.length;i++){
            for (int j = 0;j < a[0].length;j ++){
                System.out.print(a[i][j] + "   ");
            }
            System.out.println();
        }
        System.out.println(maxMatrixSum(a));
    }
}