704.二分查找

704. 二分查找

class Solution {
public:
    int search(vector<int>& nums, int target) {
        int left=0;
        int right=nums.size()-1;
        while(left<=right){
            int middle=(left+right)/2;
            if (nums[middle]>target){
                right=middle-1;
            }
            else if (nums[middle]<target){
                left=middle+1;
            }
            else{
                return middle;
            }
            
        }
        return -1;
    }
};

int search(int* nums, int numsSize, int target){

        int left=0;
        int right=numsSize-1;
        while(left<=right){
            int middle=(left+right)/2;
            if (nums[middle]>target){
                right=middle-1;
            }
            else if (nums[middle]<target){
                left=middle+1;
            }
            else{
                return middle;
            }
            
        }
        return -1;
    
}

#include<iostream>
#include<vector>
using namespace std;
int main(){
	vector <int> nums;
	int n;
	cin>>n;
	int target;
	cin>>target;
	while(n--){
		int temp;
		cin>>temp;
		nums.push_back(temp);
	}
	int left=0;
	int right=nums.size()-1;
	while(left<=right){
		int middle=(left+right)/2;
		if(nums[middle]>target){
			right=middle-1;
		}
		else if(nums[middle]<target){
			left=middle+1;
		}
		else {
			cout<<middle;
			break;
		}
		
		
	}
  
	return 0; 
}