缺大米的请参加这个刷题/Mock interview活动

jerryzzf 发表于 2020-6-11 06:29
连续第 7 天打卡，完成 3 道 Design, Two Pointers, Binary Search题：(1/3)
1. LRU Cache
2. Is Subsequ ...

楼主求加米～～～～～～漏掉了

jerryzzf 发表于 2020-6-9 14:33
连续第 6 天打卡，完成 5 道 Binary Search, Bit Manipulation, Trie, Design, DFS 题：
1. Power of Two
...

楼主求加米～～～～～～漏掉了

jerryzzf 发表于 2020-6-7 13:25
连续第 5 天打卡，完成 3 道 Binary Search, Divide & Conquer, Sort 题：
1. Find Index Equals Value
...

楼主求加米～～～～～～漏掉了

连续第 13 天打卡，完成 4 道 Sort, Two Pointers 题：(4/4)
1. Merge Intervals
2. Teemo Attacking
3. Partition Labels
4. Interval List Intersections

Tips 总结：
1. These problems are typical examples of "merge interval questions" which are now quite popular in Google;
2. Typically such problems could be solved in a linear time in the case of sorted input, like "Teemo Attacking", "Interval List Intersections";
3. Otherwise, such problems could be solved in O(NlogN) time (due to sorting preprocessing), like "Merge Intervals".

打卡第20天

打卡第二天，七题~

06/20

        • Palindrome Permutation
                if odd number > 2 -> False


        • Permutation Sequence
                ○ Sol1 DFS + recrusive
                        • list all permutations and count k
                        • be careful with permutations order, can't use swap, eg. 321 should be generated after 312
                                                                        w Need to use s store the current str, rest store the left str
                        • improve time complexity:
                                □ if self.k > math.factorial(len(res) - 1): continue
                        • Time O(n)
                ○ Sol2 Math
                        •  use a loop to check the region that the sequence number falls in and get the starting digit
                        • then we adjust the sequence number and continue. (can not swap, delect handled number)
                                □ k -= 1 -> the first permutation is itself
                                □ index, k = divmode(k, math.factorial(n)),       index -> the index of the digit need to add to permutation
                        • Time O(n)
                               

        • Print all permutations of a string (with duplicate letters)
                ○ use hashset for deduplication:
                        If use only one HashSet in the main function     Space O(n!)
                        Defined at each call - stack level           Space O(n^2)
                ○ Sol1 recursive String + Reorder O(n^2)
                ○ Sol2 recursive list + Swap O(n!)
               

打卡 day 19

今天的六题，已经连续五天，总共十天做题啦

打卡第一天，求加大米