题解 | #二分查找-I#

标签：二分法

class Solution:
    def search(self , nums: List[int], target: int) -> int:
        # 处理异常场景和如果首位元素刚好满足场景
        if len(nums) == 0:
            return -1
        elif nums[0] == target:
            return 0
        elif nums[len(nums) - 1] == target:
            return len(nums) - 1
        
        left = 0
        right = len(nums) - 1
        # 使用二分法不断缩小左右边界，来找到符合的值
        while left < right:
            mid = (left + right) // 2
            if nums[mid] < target:
                left = mid + 1
            elif nums[mid] == target:
                return mid
            else:
                right = mid
        # 当遍历完所有元素后，无满足的值，返回-1
        if nums[left] != target:
            return -1