栈

二叉树

队列

堆

排序

冒泡排序

/*
 * 冒泡排序：进行n次循环，一次循环,两两比较，必要时候交换位置
 
第一次循环：
700,0,11,800,9000,59,600,22,34,44
0,700,11,800,9000,59,600,22,34,44
0,11,700,800,9000,59,600,22,34,44
0,11,700,800,59,9000,600,22,34,44
0,11,700,800,59,600,9000,22,34,44
0,11,700,800,59,600,22,9000,34,44
0,11,700,800,59,600,22,34,9000,44
0,11,700,800,59,600,22,34,44,9000
 
第二次循环：
0,11,700,800,59,600,22,34,44
...
0,11,700,59,600,22,34,44,800
 */
- (void)bubbleSort:(NSMutableArray*)array{
    
    int i = (int)[array count]-1;
    int temp;
    
    while (i > 0) {
        
        for (int j = 0; j < i; j++) {
            if ([array[j] intValue] > [array[j+1] intValue]) {
                temp = [array[j + 1] intValue];
                array[j + 1] = array[j];
                array[j] = @(temp);
            }
        }
        i--;
    }
    NSLog(@"排序后：%@",array);
}

归并排序

先分割一个再按照大小有序合并

基数排序

查找

二分查找（折半查找）

关键点：必须是先排好序的数组，计算的到middleIndex,然后再让target和数组中middleIndex处的值进行对比

#import "ViewController.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    NSArray *array = @[@"0",@"11",@"22",@"34",@"44",@"59",@"600",@"700",@"800",@"9000"];
    
    [self binarySearchByRecursive:array target:1000000 startIndex:0 endIndex:9];
}

/*
 * 二分查找-递归
 */
- (void)binarySearchByRecursive:(NSArray*)array target:(int)target startIndex:(int)startIndex endIndex:(int)endIndex{
    
    int middleIndex = (startIndex + endIndex) / 2;
    NSLog(@"startIndex:[%d]=%@ endIndex:[%d]=%@ middleIndex:[%d]=%@",startIndex,array[startIndex],endIndex,array[endIndex],middleIndex,array[middleIndex]);
    
    if (target > [array[middleIndex] intValue]) {
        if (startIndex == endIndex) {
            NSLog(@"没找到");
            return;
        }
        NSLog(@"find+...");
        [self binarySearchByRecursive:array target:target startIndex:middleIndex+1 endIndex:endIndex];
    }else if(target < [array[middleIndex] intValue]){
        if (startIndex == middleIndex) {
            NSLog(@"没找到");
            return;
        }
        NSLog(@"find-...");
        [self binarySearchByRecursive:array target:target startIndex:startIndex endIndex:middleIndex-1];
    }else if([array[middleIndex] intValue] == target){
        NSLog(@"找到了，值是：%d",[array[middleIndex] intValue]);
    }
    
}

@end