数组中最大的子数组之和2

一、程序分析

（一）、要求

1，以指定格式的文本文件形式输入数组。

2，数组由一维变为二维。

3，熟练使用git常用命令将作业签入代码版本控制平台。

4，给出单元测试/代码覆盖率的最终覆盖率的报告,撰写博客。

（二）、实现代码

package test;
import java.io.BufferedReader;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

public class Calculate {

	public static void main(String[] args) throws IOException {

		Integer[][] c = new Integer[100][];

		c = ReadFile("C:\\Users\\玉玉的凉茶\\Desktop\\arr.txt");
		for (int i = 0; i < c.length; i++) {
			for (int j = 0; j < c[0].length; j++) {
				System.out.print(c[i][j] + " ");
			}
			System.out.println();
		}
		// System.out.print(c[2][2]);
		System.out.println("max:" + GetMaxSUM(c));
		// System.out.println("2"+MaxSUM(c));
	}

	public static Integer[][] ReadFile(String str) {
		FileReader file = null;

		try {
			file = new FileReader(str);
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
		System.out.println("文件测试数据如下：");
		BufferedReader br = new BufferedReader(file);// 读取文件
		try {
			String line = br.readLine();// 读取一行数据
			int lenx = Integer.parseInt(line);// 将数据转化为int类型
			line = br.readLine();// 读取一行数据
			int leny = Integer.parseInt(line);// 将数据转化为int类型
			// System.out.println(lines);

			String[] sp = null;
			String[][] c = new String[lenx][leny];
			Integer[][] cc = new Integer[lenx][leny];
			int count = 0;
			while ((line = br.readLine()) != null) {// 按行读取
				sp = line.split(" ");// 按空格进行分割
				// System.out.println("Length:"+sp.length);
				// System.out.println("sp:"+sp[0]);
				for (int i = 0; i < sp.length; i++) {
					c[count][i] = sp[i];
				}
				count++;
			}
			for (int i = 0; i < lenx; i++) {
				for (int j = 0; j < leny; j++) {
					cc[i][j] = Integer.parseInt(c[i][j]);
					// System.out.print(cc[i][j]+" ");
				}
				// System.out.println();
			}
			return cc;
		} catch (IOException e) {
			e.printStackTrace();
		}
		return null;
	}

	public static int GetMaxSUM(Integer[][] a) {
		int n = a.length;
		int m = a[0].length;
		// 分块
		Integer[] Max = new Integer[100];
		Integer[] Begin = new Integer[100];
		Integer[] End = new Integer[100];
		Integer[] b = new Integer[100];
		for (int i = 0; i < n; i++) {
			// 按行分组
			for (int j = 0; j < m; j++) {
				b[j] = a[i][j];

			}
			MaxIntArray(b, Max, Begin, End, m, i);
		}

		int max = Max[0];
		for (int i = 0; i < n - 1; i++) {
			if ((Begin[i] <= End[i + 1] && Begin[i] >= Begin[i + 1])
					|| (End[i] <= End[i + 1] && End[i] >= Begin[i + 1])) {
				max = Max[i + 1] + max;
			} else {
				// 如果不能直接连通，判断代价是否合适
				if (Begin[i] > End[i + 1]) {
					int t = Begin[i] - End[i + 1];
					int s = Begin[i];
					int temp = 0;
					for (int k = 0; k < t; k++) {
						temp += a[i + 1][s - k];
					}
					if (temp + Max[i + 1] > 0)
						max = temp + Max[i + 1];
				}
				if (End[i] < Begin[i + 1]) {
					int t = Begin[i + 1] - End[i];
					int s = End[i];
					int temp = 0;
					for (int k = 0; k < t; k++) {
						temp += a[i + 1][s + k];
					}
					if (temp + Max[i + 1] > 0)
						max = temp + Max[i + 1];
				}
			}
		}
		return max;
	}

	public static void MaxIntArray(Integer[] a, Integer[] max, Integer[] begin, Integer[] end, int n, int index) {

		Integer[] Max = new Integer[100];
		Max[0] = 0;
		int i = 0;// 数组下标
		int j = 0;// 最大值数组下标
		int temp = 0;// 中间变量
		// 记录子数组的起始位置和末位
		// Integer[] Bg=new Integer[100];
		Integer[] Bg = { -1, -1, -1, -1, -1 };
		Integer[] Ed = new Integer[100];
		while (i < n) {
			if (temp + a[i] >= Max[j]) {
				temp = temp + a[i];
				Max[j] = temp;
				if (Bg[j] == -1)
					Bg[j] = i;
				Ed[j] = i;
				i++;
			} else if (temp + a[i] < Max[j] && temp + a[i] > 0) {
				temp = temp + a[i];
				i++;
			} else if (temp + a[i] <= 0) {
				i++;
				j++;
				Max[j] = 0;
				temp = 0;
			}

		}
		max[index] = Max[0];
		int q = 0;
		for (int k = 0; k <= j; k++) {
			if (Max[k] > max[index]) {
				max[index] = Max[k];
				q = k;
			}
		}
		begin[index] = Bg[q];
		end[index] = Ed[q];
	}

}

　（三）、测试代码

package test;

import org.junit.Test;

import static org.junit.Assert.*;
import static test.Calculate.GetMaxSUM;
import static test.Calculate.ReadFile;

public class CalculateTest {

    @Test
    public void test1() {
        String str="C:\\Users\\玉玉的凉茶\\Desktop\\arr1.txt";
        Integer[][] c=ReadFile(str);
        System.out.println("MaxSUM:"+GetMaxSUM(c));
    }
    @Test
    public void test2() {
        String str="C:\\Users\\玉玉的凉茶\\Desktop\\arr2.txt";
        Integer[][] c=ReadFile(str);
        System.out.println("MaxSUM:"+GetMaxSUM(c));
    }
    @Test
    public void test3() {
        String str="C:\\Users\\玉玉的凉茶\\Desktop\\arr3.txt";
        Integer[][] c=ReadFile(str);
        System.out.println("MaxSUM:"+GetMaxSUM(c));
    }
    @Test
    public void test4() {
        String str="C:\\Users\\玉玉的凉茶\\Desktop\\arr4.txt";
        Integer[][] c=ReadFile(str);
        System.out.println("MaxSUM:"+GetMaxSUM(c));
    }

}