二分查找算法的3种模板-PYTHON

class binary_search(object):
    def __init__(self, nums, target):
        self.nums = nums
        self.target = target

    def binary_search_template_1(self):
        if len(self.nums) == 0:
            return -1
        l, r = 0, len(self.nums) - 1
        while (l <= r):
            mid = (l + r) // 2
            if self.nums[mid] == self.target:
                return mid
            elif self.nums[mid] < self.target:
                l = mid + 1
            else:
                r = mid - 1
        return -1

    def binary_search_template_2(self):
        if len(self.nums) == 0:
            return -1
        l, r = 0, len(self.nums)
        while l < r:
            mid = (l + r) // 2
            if self.nums[mid] == self.target:
                return mid
            elif self.nums[mid] < self.target:
                l = mid + 1
            else:
                r = mid
        if l != len(self.nums) and nums[l] == self.target:
            return l
        return -1

    def binary_search_template_3(self):
        if len(self.nums) == 0:
            return -1
        l, r = 0, len(self.nums) - 1
        while l + 1 < r:
            mid = (l + r) // 2
            if self.nums[mid] == self.target:
                return mid
            elif self.nums[mid] < self.target:
                l = mid
            else:
                r = mid
        if self.nums[l] == self.target:
            return l
        if self.nums[r] == self.target:
            return r
        return -1