title: 查找
date: 2022-08-18 14:59:55
tags:
- 数据结构
categories:
- 408
- 数据结构
- 代码
看到有序数组首先想能不能折半查找
折半查找
#include <iostream>
#include <vector>
using namespace std;
/**
* @description:
* @param {int} target 目标函数
* @param {int} arr 数组
* @param {int} len 长度
* @return {*} 找到 返回mid,未找到返回-1
*/
int binary_search(int target, int arr[], int len){
int l = 0, r = len - 1, mid;
while (l < r)
{
mid = l + (r - l)/2; //防止int溢出
if(arr[mid] < target)
l = mid + 1;
else if(target < arr[mid])
r = mid -1;
else
return mid;
}
// return l; // 返回插入位置
return -1;
}
//第二种写法
int binary_search(int target, int arr[], int len){
int l = 0, r = len - 1, mid;
while (l < r)
{
mid = l + (r - l)/2; //防止int溢出
if(arr[mid] == target)
return mid;
else if(target < arr[mid])
r = mid - 1;
else
l = mid + 1;
}
return -1;
}
int main(int argc, char const *argv[])
{
int arr[] = {1, 2, 4, 6, 7, 10, 11, 19, 24, 30};
int target = 4;
int len = sizeof(arr)/sizeof(int) - 1;
printf("target: %d, pos: %d\n", target, binary_search(target, arr, len));
return 0;
}
标签:arr,return,target,int,mid,len,查找
From: https://www.cnblogs.com/yinqiyu/p/16906620.html