c++数组---二分查找

二分查找

在数组升序的条件下，寻找目标值target，找到返回其下标。

#include 
#include 
using namespace std;

class Solution {
public:

	int serach(vector &nums, int target) {
		int right = nums.size() - 1;
		int left = 0;

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

void test01()
{
	vector v1;
	Solution a;
	int m;
	
	v1.push_back(1);
	v1.push_back(3);
	v1.push_back(5);
	v1.push_back(7);
	v1.push_back(8);
	v1.push_back(9);
	m = a.serach(v1, 3);
	cout << m;

}


int main()
{
	test01();

	system("pause");
	return 0;
}