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iterative quick sort.cpp
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iterative quick sort.cpp
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#include <bits/stdc++.h>
using namespace std;
void swap(int* a, int* b)
{
int t = *a;
*a = *b;
*b = t;
}
int partition(int arr[], int l, int h)
{
int x = arr[h];
int i = (l - 1);
for (int j = l; j <= h - 1; j++) {
if (arr[j] <= x) {
i++;
swap(&arr[i], &arr[j]);
}
}
swap(&arr[i + 1], &arr[h]);
return (i + 1);
}
void quickSortIterative(int arr[], int l, int h)
{
int stack[h - l + 1];
int top = -1;
stack[++top] = l;
stack[++top] = h;
while (top >= 0) {
h = stack[top--];
l = stack[top--];
int p = partition(arr, l, h);
if (p - 1 > l) {
stack[++top] = l;
stack[++top] = p - 1;
}
if (p + 1 < h) {
stack[++top] = p + 1;
stack[++top] = h;
}
}
}
void printArr(int arr[], int n)
{
int i;
for (i = 0; i < n; ++i)
cout << arr[i] << " ";
}
// Driver code
int main()
{
int arr[] = { 4, 3, 5, 2, 1, 3, 2, 3 };
int n = sizeof(arr) / sizeof(*arr);
quickSortIterative(arr, 0, n - 1);
printArr(arr, n);
return 0;
}