经典排序算法(OC实现版)

排序算法是每个程序猿都必须掌握的算法。通过思想的转化，排序算法可能用在很多实际应用中。如统计数组的逆序对(归并算法)，数组中出现次数超过一半的数字(快速排序)，最小的k个数(堆排序)。算法的思路不细讲了，网上的文章很多。直接上代码:

头文件如下：

#import 

@interface Sort : NSObject

//快速排序
-(void)quickSortWithArray:(NSArray *)arrData;

//冒泡排序
-(void)bubbleSortWithArray:(NSArray *)arrData;

//堆排序
-(void)heapSortWithArray:(NSArray *)arrData;

//归并排序
-(NSArray *)mergeSortWithArray:(NSArray *)arrData;

@end

实现文件：

//
//  Sort.m
//  quickSort
//
//  Created by bcc_cae on 16/7/4.
//  Copyright © 2016年 bcc_cae. All rights reserved.
//

#import "Sort.h"
//#import "JWLKitMacro.h"

@implementation Sort

#pragma mark -quickSort

-(void)quickSortWithArray:(NSArray *)arrData
{
    NSMutableArray *data = [[NSMutableArray alloc] initWithArray:arrData];
    [self quickSortWithArray:data left:0 right:[data count] -1 ];
    NSLog(@"快速排序后的结果:%@",[data description]);
}

-(void)quickSortWithArray:(NSMutableArray *)arrData  left:(NSUInteger)left right:(NSUInteger)right
{
    if(right > left){
    NSUInteger i = left;
    NSUInteger j = right + 1;
    while (true) {
        while (i+1<[arrData count] && [arrData objectAtIndex:++i] < [arrData objectAtIndex:left]);
        while ([arrData objectAtIndex:--j]>[arrData objectAtIndex:left]);
        
        if (i>=j) {
            break;
        }
        
        //JWL_SWAP([arrData objectAtIndex:i], [arrData objectAtIndex:j]);
        
        [self swapWithData:arrData index1:i index2:j];
    }
    [self swapWithData:arrData index1:left index2:j];
    [self quickSortWithArray:arrData left:left right:j-1];
    [self quickSortWithArray:arrData left:j+1 right:right];
    }
}


-(void)swapWithData:(NSMutableArray *)arrData index1:(NSUInteger)index1  index2:(NSUInteger)index2
{
    NSNumber *temp = [arrData objectAtIndex:index1];
    [arrData replaceObjectAtIndex:index1 withObject:[arrData objectAtIndex:index2]];
    [arrData replaceObjectAtIndex:index2 withObject:temp];
}

#pragma mark -bubbleSort
//冒泡排序
-(void)bubbleSortWithArray:(NSMutableArray *)arrData{
    for (int i=0; i[arrData objectAtIndex:j]) {
                [self swapWithData:arrData index1:j-1 index2:j];
            }
        }
    }
}

#pragma mark --heap
//调整堆
-(void)heapAdjust:(NSMutableArray *)arrData index:(NSUInteger)index  length:(NSUInteger)length
{
    NSUInteger left = 2 * index+1;
    NSUInteger right = 2 * index +2;
    
    NSUInteger max = index;
    
    if (index<=length/2) {
        if (left[arrData objectAtIndex:max]) {
            max = left;
        }
        
        if (right [arrData objectAtIndex:max]) {
            max  = right;
        }
        
        if (max != index) {
            [self swapWithData:arrData index1:max  index2:index];
            [self heapAdjust:arrData index:max length:length];
        }
    }
    
}

//建堆
-(void)buildHeap:(NSMutableArray *)arrData  length:(NSUInteger)length
{
    for (int i=length/2-1; i>=0; --i) {
        [self heapAdjust:arrData index:i length:length];
    }
}

//堆排序
-(void)heapSortWithArray:(NSMutableArray *)arrData length:(NSUInteger)length
{
    [self buildHeap:arrData length:length];
    
    for (int i=length-1; i>=0; --i) {
        [self swapWithData:arrData index1:0 index2:i];
        
        [self heapAdjust:arrData index:0 length:i];
    }
}

-(void)heapSortWithArray:(NSArray *)arrData
{
    [self heapSortWithArray:arrData length:arrData.count];
}


#pragma mark  mergeSort

-(NSArray *)mergeWithLeftArray:(NSArray *)leftArray rightArray:(NSArray *)rigthArray
{
    int l = 0;
    int r = 0;
    NSMutableArray *resultArray = [NSMutableArray array];
    
    while (lrigthArray.lastObject)?leftArray.lastObject:rigthArray.lastObject];
    
    return resultArray;
}


-(NSArray *)mergeSortWithArray:(NSArray *)arrData
{
    if(arrData.count <=1 )    return arrData;
    
    NSInteger mid = arrData.count/2;
    NSArray *leftArray = [self mergeSortWithArray:[arrData subarrayWithRange:NSMakeRange(0, mid)]];
    NSArray *rightArray = [self mergeSortWithArray:[arrData subarrayWithRange:NSMakeRange(mid,arrData.count-mid)]];
    
    return [self mergeWithLeftArray:leftArray rightArray:rightArray];
}


@end

因个人能力有限，如有写的不对的地方或者效率问题，请指出，谢谢！