iOS 冒泡排序、二分法查找、快排、哈希排序

// 冒泡排序
- (void)bubbleSort {
    NSMutableArray *array = [NSMutableArray arrayWithArray:@[@"98",@"75",@"89",@"53",@"67",@"92"]];
    for (int i = 0; i < array.count - 1; i++) {
        for (int j = 0; j < array.count-1-i; j++) {
            //原理：从第1个数开始起，与后面的数字相互比较，满足条件的向后位移（值交换），若不满足条件，拿到大一点的数值继续向后比较
            if ([array[j] intValue] > [array[j+1] intValue]) {
                // 开始交换数据
                NSString *temp = array[j];
                array[j] = array[j+1];
                array[j+1] = temp;
            }
        }
        NSLog(@"%@",array);
    }
}

---

// 选择排序
- (void)selectSort {
    NSMutableArray *array = [NSMutableArray arrayWithArray:@[@"98",@"75",@"89",@"53",@"67",@"92"]];
    for (int i = 0; i < array.count-1; i++) {
        // 原理：从i后面第i+1个数起，跟array[i]相互比较，满足条件即交换值
        for (int j = i+1; j < array.count; j++) {
            // if里面的 '>' '<' 条件决定了排序的 升降
            if ([array[i] intValue] > [array[j] intValue]) {
                NSString *temp = array[j];
                array[j] = array[i];
                array[i] = temp;
            }
        }
        NSLog(@"%@",array);
    }
}

---

// 二分法查找
- (void)binarySearch {
    // OC方法实现二分法：indexOfObject:inSortedRange:options:usingComparator:
    /*
    NSArray *sortedArray = ... // must be sorted
    id searchObject = ...
    NSRange searchRange = NSMakeRange(0, [sortedArray count]);
    NSUInteger findIndex = [sortedArray indexOfObject:searchObject
                                    inSortedRange:searchRange
                                          options:NSBinarySearchingFirstEqual
                                  usingComparator:^(id obj1, id obj2)
                        {
                            return [obj1 compare:obj2];
                        }];

    */


    NSArray *numberArray = @[@1, @3, @27, @36, @42, @70, @82];

    NSNumber *searchNum = @70;

    NSUInteger mid;
    NSUInteger min = 0;
    NSUInteger max = [numberArray count] - 1;

    BOOL found = NO;

    while (min <= max) {
    
          mid = (min + max)/2;
    
          if ([searchNum intValue] == [numberArray[mid] intValue]) {
            NSLog(@"We found the number! It is at index %lu", mid);
            found = YES;
            break;
        } else if ([searchNum intValue] < [numberArray[mid] intValue]) {
            max = mid - 1;
        } else if ([searchNum intValue] > [numberArray[mid] intValue]) {
            min = mid + 1;
        }
    }
    if (!found) {
        NSLog(@"The number was not found.");
    }
}

---

 // 快排和希尔排序
 //  Created by 葛朋 on 2018/5/26.
- (void)viewDidLoad {
    [super viewDidLoad];

    NSMutableArray *arr = [[NSMutableArray alloc] initWithObjects:@(6), @(1),@(2),@(5),@(9),@(4),@(3),@(7),@(100),@(80),@(88),@(30),@(35),@(20),@(14),@(34),@(88),@(83),nil];

    NSDate* dat = [NSDate dateWithTimeIntervalSinceNow:0];

    NSTimeInterval a=[dat timeIntervalSince1970];

    //  [self quickSortArray:arr withLeftIndex:0 andRightIndex:arr.count - 1];
      [self xierAry:arr];
    NSDate* dat2 = [NSDate dateWithTimeIntervalSinceNow:0];

    NSTimeInterval a2 =[dat2 timeIntervalSince1970];
    NSLog(@"%@--时间:%f",arr,(a2 - a));

}


- (void)xierAry:(NSMutableArray *)ary{

    NSInteger n = ary.count;

    for (NSInteger gap = n/2 ; gap > 0; gap /= 2) {
        for (NSInteger i = gap; i < n; i++) {
            for (NSInteger j = i - gap; j>= 0 && ary[j] > ary[j+ gap]; j-= gap) {
                [ary exchangeObjectAtIndex:j withObjectAtIndex:(j+gap)];
            }
        }
    }

}

- (void)quickSortArray:(NSMutableArray *)array withLeftIndex:(NSInteger)leftIndex andRightIndex:(NSInteger)rightIndex
{
    if (leftIndex >= rightIndex) {//如果数组长度为0或1时返回
        return ;
    }

    NSInteger i = leftIndex;
    NSInteger j = rightIndex;
    //记录比较基准数
    NSInteger key = [array[i] integerValue];

    while (i < j) {
        /**** 首先从右边j开始查找比基准数小的值 ***/
        while (i < j && [array[j] integerValue] >= key) {//如果比基准数大，继续查找
            j--;
        }
        //如果比基准数小，则将查找到的小值调换到i的位置
        array[i] = array[j];
    
        /**** 当在右边查找到一个比基准数小的值时，就从i开始往后找比基准数大的值 ***/
        while (i < j && [array[i] integerValue] <= key) {//如果比基准数小，继续查找
             i++;
        
         }
        //如果比基准数大，则将查找到的大值调换到j的位置
        array[j] = array[i];
    
    }

    //将基准数放到正确位置
    array[i] = @(key);

    /**** 递归排序 ***/
    //排序基准数左边的
    [self quickSortArray:array withLeftIndex:leftIndex andRightIndex:i - 1];
    //排序基准数右边的
    [self quickSortArray:array withLeftIndex:i + 1 andRightIndex:rightIndex];
 }

特别感谢 葛朋 快排、希尔排序
Created by 葛朋 on 2018/5/26.