Offer 53 - I. 在排序数组中查找数字 I（search）

Offer 53 - I. 在排序数组中查找数字 I（search）

1. python

class Solution:
    def search(self, nums: List[int], target: int) -> int:
        # cnt=0
        # for v in nums:
        #     if target ==v:
        #         cnt+=1
        # return cnt
        def helper(target):
            i,j = 0,len(nums)-1
            while i<=j:
                mid = (i+j)//2
                if target<nums[mid]:
                    j=mid-1
                else:
                    i=mid+1
            return i
        return helper(target)-helper(target-1)
        

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2. Java

public class Solution {
    // you need to treat n as an unsigned value
    public int hammingWeight(int n) {
        int cnt = 0;
        while (n!=0){
            cnt+=1;
            n=n&(n-1);
        }
        return cnt;
        
    }
}
class Solution {
    public int search(int[] nums, int target) {
        return helper(nums,target)-helper(nums,target-1);
        
    }
    int helper(int [] nums,int target){
        int i=0,j=nums.length-1;
        while(i<=j){
            int mid=(i+j)/2;
            if(nums[mid]>target){
                j=mid-1;
            }else{
                i=mid+1;
            }
        }
        return i;
    }
}

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