Maximized array sum after 13 K negations

13 K The maximum array and... After negation

author : Turbo The time limit : 1S chapter :  curriculum design

Problem description :

Give you an array of integers nums And an integer k , Modify the array as follows ：

     Select a subscript i And will nums[i] Replace with -nums[i] .

Repeating this process happens to k Time . You can select the same subscript multiple times i .

After modifying the array in this way , Returns an array of The maximum possible and .

Example 1：

Input ：

3

4 2 3

1

Output ：5

explain ： Select subscript 1 ,nums Turn into [4,-2,3] .

Example 2：

Input ：

4

3 -1 0 2

3

Output ：6

explain ： Select subscript (1, 2, 2) ,nums Turn into [3,1,0,2] .

Example 3：

Input ：

5

2 -3 -1 5 -4

2

Output ：13

explain ： Select subscript (1, 4) ,nums Turn into [2,3,-1,5,4] .

Enter description :

Enter three lines ：

Enter an integer in the first line n Represents an array nums The length of .

Second line input n Integers represent the elements of the array .

On the third line, enter an integer representation k.

Tips ：

    1 <= n <= 10^4

    -100 <= nums[i] <= 100

    1 <= k <= 10^4

The output shows that :

Output an integer to represent the result .

Input example :

4
1 2 3 4
3

Output example :

8、

Classification seems a little complicated But the answer is correct I have to upload it quickly, students It's too late to explain It's almost over

#include<iostream>
#include<algorithm>
using namespace std;
int negative_number = 0;
int zero_nuumber = 0;
bool cmp(int x, int y)
{
	return x < y;
}
int main()
{
	int arr[100001] = { 0 };
	int n = 0;
	cin >> n;
	for (int i = 0; i < n; i++)
	{
		cin >> arr[i];
		if (arr[i] < 0)
		{
			negative_number++;
		}
		else if (arr[i] == 0)
		{
			zero_nuumber++;
		}
	}

	int k = 0;
	cin >> k;

	if (negative_number > 0)// There are negative numbers 
	{
		int total = 0;
		sort(arr, arr + n, cmp);
		if (k > n)
		{
			if (k % 2 == 0)
			{
				for (int i = 0; i < n; i++)
				{
					if (arr[i] < 0)
					{
						arr[i] = -arr[i];
					}
				}
				for (int i = 0; i < n; i++)
				{
					total += arr[i];
				}
			}
			else if (k % 2 != 0)
			{
				if (zero_nuumber > 0)
				{
					for (int i = 0; i < k; i++)
					{
						arr[i] = -arr[i];
						if (arr[i] == 0)
						{
							break;
						}
					}
					for (int i = 0; i < n; i++)
					{
						total += arr[i];
					}
				}
				else if (zero_nuumber == 0)
				{
					for (int i = 0; i < n; i++)
					{
						if (arr[i] < 0)
						{
							arr[i] = -arr[i];
						}
					}
					sort(arr, arr + n, cmp);
					arr[0] = -arr[0];
					for (int i = 0; i < n; i++)
					{
						total += arr[i];
					}
				}
			}
			cout << total;
		}
		else if (k <= n)
		{
			if (k < negative_number)
			{

				for (int i = 0; i < k; i++)
				{
					arr[i] = -arr[i];
				}
				for (int i = 0; i < n; i++)
				{
					total += arr[i];
				}
			}
			else if (k > negative_number)
			{
				if (zero_nuumber > 0)
				{
					for (int i = 0; i < k; i++)
					{
						if (arr[i] < 0)
						{
							arr[i] = -arr[i];
						}
						else if (arr[i] == 0)
						{
							break;
						}
					}
					for (int i = 0; i < n; i++)
					{
						total += arr[i];
					}
				}
				else if (zero_nuumber == 0)
				{
					for (int i = 0; i < k; i++)
					{
						if (arr[i] < 0)
						{
							arr[i] = -arr[i];
						}
					}
					for (int i = 0; i < n; i++)
					{
						total += arr[i];
					}
				}
			}	
			cout << total;
		}

	
	}
	else if (negative_number == 0)// All numbers are positive 
	{
		if (k % 2 == 0)
		{
			int total = 0;
			for (int i = 0; i < n; i++)
			{
				total += arr[i];
			}
			cout << total;
		}
		else if (k % 2 != 0)
		{
			int total = 0;
			sort(arr, arr + n, cmp);
			arr[0] = -arr[0];
			for (int i = 0; i < n; i++)
			{
				total += arr[i];
			}
			cout << total;
		}
	}

	

	return 0;

}