堆排序相关

Posted 2021-11-29 --chenshou--

代码如下

#include<bits/stdc++.h>
using namespace std;

#define max_len 1000

void heapify( int tree [] , int n , int i ){
    
    if( i >= n )return ;
    
    int c1 = 2 * i + 1 ;
    int c2 = 2 * i + 2 ;
    int maxx = i ;
    if( c1 < n && tree[c1] > tree [maxx] ) maxx = c1 ;
    if( c2 < n && tree[c2] > tree [maxx] ) maxx = c2 ;
    if ( maxx != i ){
        swap( tree[maxx] , tree[i] );
        heapify( tree , n , maxx );
    }
}

void build_heap(int tree[], int n){
    int last_node = n-1 ;
    int parent = ( last_node - 1 ) / 2;
    for(int i = parent;i>=0;i-- ){
        heapify(tree , n , i );
    }
}

void heap_sort(int tree[],int n){
    build_heap(tree,n);
    for(int i=n-1;i>=0;i--){
        swap(tree[i],tree[0]);
        heapify(tree,i,0);
    }
}

int main(){
    int tree[]={2 ,5 ,3 ,1 ,10 ,4 };
    int n=6;
    heap_sort(tree,n);
    //heapify( tree , n , 0);
    for(int i=0;i<n;i++)printf("%d\n",tree[i]);
    return 0;
    
}