二分查找算法(OC版--非递归实现)

来源：互联网发布：生鲜配送app源码编辑：程序博客网时间：2024/04/29 01:28

闲来无事，写写二分查找算法，如有bug，请指出

////  ViewController.m//  BinarySearch////  Created by bcc_cae on 16/3/25.//  Copyright © 2016年 bcc_cae. All rights reserved.//#import "ViewController.h"@interface ViewController ()@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];    // Do any additional setup after loading the view, typically from a nib.    NSArray *arr = @[@1,@3,@5,@7,@9,@10,@12];    int result = [self BinarySearch:arr target:@13];    NSLog(@"%d",result);    }- (int)BinarySearch:(NSArray *)arr target:(int)target{    if (!arr.count) {        return -1;    }    unsigned int  low = 0;    unsigned int  high = arr.count - 1;        while (low<=high) {        unsigned int mid = low + ((high-low)>>1); //防止加法溢出        int  num = [arr objectAtIndex:mid];        if (target == num) {            return low;        }else if(num > target)        {            high = mid -1;        }else{            low = mid +1;        }    }    return -1;}- (void)didReceiveMemoryWarning {    [super didReceiveMemoryWarning];    // Dispose of any resources that can be recreated.}@end

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