软件工程第三次作业

一、题目要求

问题：

给定n个整数（可能为负数）组成的序列a[1],a[2],a[3],…,a[n],求该序列如a[i]+a[i+1]+…+a[j]的子段和的最大值。当所给的整数均为负数时定义子段和为0，依此定义，所求的最优值为： Max{0,a[i]+a[i+1]+…+a[j]},1<=i<=j<=n。

例如，当（a[1],a[2],a[3],a[4],a[5],a[6]）=(-2,11,-4,13,-5,-2)时，最大子段和为20。

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二、编写代码
代码托管所地址：https://git.dev.tencent.com/TianyiZhang/software-engineering.git

#include<stdio.h>
#include<stdlib.h>
int MaxSubseqSum4(int a[], int n)
{
	int i = 0;
	int thisSum = 0, sum = 0;
	for (i = 0; i < n; i++) {
		thisSum += a[i];
		if (thisSum > sum) {
			sum = thisSum;
		}
		else if (thisSum <= 0) {
			thisSum = 0;
		}
	}
	return sum;
}

int main()
{
	int a[1000], n, i,m;
	scanf_s("%d", &n);
	for (i = 0; i < n; i++)
	{
		scanf_s("%d", &a[i]);
	}
	m=MaxSubseqSum4(a, n);
	printf("%d", m);
	system("pause");
	return 0;
}

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三、代码流程图

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四、测试代码

· 测试结果情况：

1、输入整数n<0.
2、整数元素均为负数.
3、整数元素均为正数.
4、最大子段和在后.
5、最大子段和在前.

#include "stdafx.h"
#include "CppUnitTest.h"
#include"../软工第三次作业/标头.h"

using namespace Microsoft::VisualStudio::CppUnitTestFramework;

namespace UnitTest1
{		
	TEST_CLASS(UnitTest1)
	{
	public:
		TEST_METHOD(TestMethod1)
		{
			int a[] = { 0 };
			int n = -1;
			Assert::AreEqual(MaxSubseqSum4(a, n), 0);
		}
		TEST_METHOD(TestMethod2)
		{
			int a[] = { -1,-2,-3,-4. - 5 };
			int n = 5;
			Assert::AreEqual(MaxSubseqSum4(a, n), 0);
		}
		TEST_METHOD(TestMethod3)
		{
			int a[] = { 1,2,3,4,5 };
			int n = 5;
			Assert::AreEqual(MaxSubseqSum4(a, n), 15);
		}
		TEST_METHOD(TestMethod4)
		{
			int a[] = { 4,5,-6,-7,10 };
			int n = 5;
			Assert::AreEqual(MaxSubseqSum4(a,n), 10);
		}
		TEST_METHOD(TestMethod5)
		{
			int a[] = { 4,5,-6,-7,8 };
			int n = 5;
			Assert::AreEqual(MaxSubseqSum4(a, n), 9);
		}
	};
}

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五、单元测试结果

· 单元测试结果如下：