algorithmLearing

数组相关

二分查找

对应leetcode题目

https://leetcode-cn.com/problems/binary-search/

思路

将有序排列的不重复的数组从中间分开,每次和要找的值在中点比较,如果值小于中点,则上修改有边界,否则修改左边界.

function search(nums: number[], target: number): number {
    let l  = 0;
    let r= nums.length-1;
    while(l<=r){
        let  m = (l+r)>>1;
        if(nums[m]==target){
            return m
        }
        let isSmall = nums[m]>target?true:false;
      	l = isSmall?l:m+1;
      	r = isSmall?m-1:r;
    }
    return -1
};