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# 一、快速排序

``````
int getPivot(vector<int>& arr, int left, int right){
int tmp = arr[left];
while(left < right){
while(left < right && arr[right] >= tmp){
right --;
}
arr[left] = arr[right];
while(left < right && arr[left] <= tmp){
left ++;
}
arr[right] = arr[left];
}
arr[left]  = tmp;
return left;
}

void quickSort(vector<int>& arr, int left, int right){
if(left < right){
int pivot = getPivot(arr, left, right);
quickSort(arr,left, pivot - 1);
quickSort(arr, pivot + 1, right);
}
}

``````

# 二、冒泡排序

``````void bubbleSort(vector<int>& arr){
int size = arr.size();
for(int i = 1; i < size; i++){
for(int j = 0; j < size - i; j++){
if(arr[j] > arr[j + 1]){
swap(arr[j], arr[j + 1]);
}
}
}
}
``````

# 三、堆排序

``````void adjustHeap(vector<int>& arr, int start, int end){
int parent = start;
int child = start*2 + 1;
while(child <= end){
if(child + 1 <= end && arr[child] < arr[child + 1] ){
child++;
}
if(arr[parent] > arr[child]){
return;
}
swap(arr[parent], arr[child]);
parent = child;
child = child * 2 + 1;
}
}
void heapSort(vector<int>& arr){
int size = arr.size();
for(int i = size/2 - 1; i >= 0; i--){
}
for(int i = size - 1; i >= 0; i--){
swap(arr[0], arr[i]);
}
}
``````

# 四、归并排序

``````void merge(vector<int>& arr, int left, int mid, int right){
vector<int> tmp;
int i = left, j = mid + 1;
while(i <= mid && j <= right){
if(arr[i] < arr[j]){
tmp.emplace_back(arr[i++]);
}else{
tmp.emplace_back(arr[j++]);
}
}
while(i <= mid){
tmp.emplace_back(arr[i++]);
}
while(j <= right){
tmp.emplace_back(arr[j++]);
}
int m = left;
int n = 0;
while(m <= right){
arr[m++] = tmp[n++];
}
}

void mergeSort(vector<int>& arr, int left, int right){
if(left >= right) return;
int mid = left + ((right - left) >> 1);
mergeSort(arr, left, mid);
mergeSort(arr, mid + 1, right);
merge(arr, left, mid, right);
}
``````