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QuickSort_standard.cpp
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QuickSort_standard.cpp
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//TC=O(n^2)
int partition(int arr[],int l,int h){
//making the first element of given array as pivot
int pivot=arr[l];
vector<int> temp;
for(int i=l;i<=h;i++){
if(arr[i] < pivot){
temp.push_back(arr[i]);
}
}
int partitionedIndex=temp.size()+l;
for(int i=l;i<=h;i++){
if(arr[i] == pivot){
temp.push_back(arr[i]);
}
}
for(int i=l;i<=h;i++){
if(arr[i] > pivot){
temp.push_back(arr[i]);
}
}
//most important step
for(int i=l;i<=h;i++){
arr[i]=temp[i-l];
}
return partitionedIndex;
}
void QuickSort(int arr[],int l,int h){
if(l >= h)return;
//getting the partitioned index after the partitioning..
int pIndex=partition(arr,l,h);
QuickSort(arr,l,pIndex-1);
QuickSort(arr,pIndex+1,h);
}
//OR
/*
int partitionArray(vector<int> &nums, int low, int high) {
if (low >= high) return -1;
int pivot = low, l = pivot + 1, r = high;
while (l <= r)
if (nums[l] < nums[pivot]) l++;
else if (nums[r] >= nums[pivot]) r--;
else swap(nums[l], nums[r]);
swap(nums[pivot], nums[r]);
return r;
}
void quickSort(vector<int> &nums, int low, int high) {
if (low >= high) return;
int pivot = partitionArray(nums, low, high);
quickSort(nums, low, pivot);
quickSort(nums, pivot + 1, high);
}
*/