【面試準備】堆排

#include <iostream>
using namespace std;

void AdjastHeapSort(int a[],int i,int n){//調整節點i,數組共有n個節點
	if(n == 1||i >(n-2)/2){
		return ;
	}
	int iLeft = 2*i+1;//i從0開始
	int iRight = 2*i+2;

	if(iRight<=n-1){
		if(a[i]>=a[iLeft]&&a[i]>=a[iRight]){
			return ;
		}
		if(a[i]<a[iLeft]&&a[iRight]<=a[iLeft]){
			int temp = a[iLeft];
			a[iLeft] = a[i];
			a[i] = temp;
			AdjastHeapSort(a,iLeft,n);
			return ;
		}
		if(a[i]<a[iRight]&&a[iLeft]<=a[iRight]){
			int temp = a[iRight];
			a[iRight] = a[i] ;
			a[i] = temp;
			AdjastHeapSort(a,iRight,n);
			return ;
		}
	}
	else{
		if(a[i]>=a[iLeft]){
			return ;
		}
		else{
			int temp = a[iLeft];
			a[iLeft] = a[i];
			a[i] = temp;
			AdjastHeapSort(a,iLeft,n);
			return ;
		}
	}
}

void CreateHeap(int a[],int n){
	int iFirst = (n-2)/2;
	for(;iFirst>=0;iFirst--){
		AdjastHeapSort(a,iFirst,n);
	}
}

void HeapSort(int a[],int n){
	CreateHeap(a,n);

	int temp;
	for(int i = 0;i<n-1;i++){
		temp = a[n-i-1];
		a[n-i-1] = a[0];
		a[0] = temp;
		AdjastHeapSort(a,0,n-i-1);
	}
}

int main() {
	int a[] = {1,2,3,5,343,5,3,2,4,2,2,23};
	HeapSort(a,12);
	for(int i = 0 ; i < 12 ;++ i){
		cout<<a[i]<<" ";
	}
	cout<<endl;
	return 0;
}