在已有排序的列表中,如果需要高性能查找特定数,使用二分查找;即使是无序列表,也可以先采用O(nlogn)时间复杂度下排序,再二分查找也是不错的选择
def binary_search(li, left, right, num): while left < right: mid = (left + right) // 2 if li[mid] == num: return mid elif li[mid] > num: right = mid else: left = mid if __name__ == '__main__': data = [e for e in range(1000)] res = binary_search(data, 0, len(data), 23) print(res, data[res])