Tuesday, August 2, 2022

327. Count of Range Sum

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 一刷 08/2022 Version #2 Merge Sort 看某一个prefix index后面有多少个prefix满足lower <= prefix[j]-prefix[i] <= upper Time O(NlogN) Space O(N) Runtime...
Monday, August 1, 2022

460. LFU Cache

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 一刷 08/2022 Version #1 Map of DoublyLinkedList Time O(1) for all Space O(N) - N is number of keys Runtime:  67 ms , faster than  95.05%  of ...

715. Range Module

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 一刷 07/2022 Version #1 TreeMap 思路比较简单就是把interval用key-value pair的形式存在treemap里面，然后维持所有的invervals没有overlap 需要特别处理的case exists [8, 9) add [1,8) ...

1396. Design Underground System

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 一刷 07/2022 Version #1 HashMap Time O(1) Space O(N^2 + P) - N is number of stations, P is number of passengers Runtime:  235 ms , faster tha...

995. Minimum Number of K Consecutive Bit Flips

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 一刷 07/2022 Version #1 Sliding Window 感觉很难，照着答案写还是一知半解的感觉 Time O(N) Space O(N) Runtime:  11 ms , faster than  50.79%  of Java online submiss...
Saturday, July 30, 2022

1136. Parallel Courses

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 一刷 07/2022 Version #1 Topological Sort Time O(N + E) Space O(N + E) Runtime:  6 ms , faster than  97.21%  of Java online submissions for Pa...
Friday, July 29, 2022

486. Predict the Winner

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 一刷 07/2022 Version #1 DP game theory Time O(N^2) Space O(N^2) - space can be optimized to O(N) Runtime:  0 ms , faster than  100.00%  of Ja...