sqlengineer007的博客

#217. Contains DuplicateGiven an integer array nums, return true if any value appears at least twice in the array, and return false if every element is distinct.Example 1:Input: nums = [1,2,3,1]Output: trueExample 2:Input: nums = [1,2,3,4]Output: fals

【代码】D01- leetcode 121. Best Time to Buy and Sell Stock。

what is big O notation?The way that describe the relationship between the runing time and the size of problem.1- Method of calculating time complexity of algorithm.1)hypothesis(假设法)class solution{ int i = 0; while(i <= n){ i = i * 2; }}assumi