#include <iostream>
using namespace std;
void quickSort(int left, int right, int a[])
{
int pivot = a[left];
int i = left;
int j = right;
if(left > right)
return;
while(i < j)
{
while(a[j] >= pivot && i < j)
{
j--;
}
while(a[i] <= pivot && i < j)
{
i++;
}
if(i < j)
swap(a[i], a[j]);
}
swap(a[j], a[left]);
quickSort(left, j - 1, a);
quickSort(j + 1, right, a);
};
void swap(int& a, int& b)
{
int temp = a;
a = b;
b = temp;
}
void findPairs(int a[], int length, int target)
{
int i = 0;
int j = length - 1;
while(i < j)
{
if(a[i] + a[j] < target)
i++;
else if(a[i] + a[j] > target)
j--;
else
{
printf("%d + %d = %d\n", a[i], a[j], target);
i++;
j--;
}
}
};
int main()
{
int a[5] = {5, 4, 3, 2, 1};
quickSort(0, 4, a);
for(int i = 0; i < 5; i++)
{
cout << a[i] << endl;
}
findPairs(a, 5, 6);
return 0;
}