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LC215 Kth Largest Element in an Array

Kth Largest Element in an Array

Posted by freeCookie🍪 on August 29, 2019

Leetcode H-Index

H - Index 人这一生能有多少痛苦？能做错多少选择？我好痛苦。我本不该如此的。 274. H-Index 计算h - index：”A scientist has index h if hof his/her N papers have at least h citations e...

Posted by freeCookie🍪 on August 28, 2019

Leetcode - Win the Game

LC292, LC293, LC294, LC464, LC375, LC486, LC877, LC1140

Win the Game LC上有一系列各种Game的题，都是Minimax算法。简而言之，player1赢 = player2输。那么状态转换大概就是player1点的最大值基于上一步player2的最小值。 292. Nim Game 一堆石头每次拿1-3个问先手能否赢。很简单，如果...

Posted by freeCookie🍪 on August 26, 2019

Leetcode - Word Break

LC139, LC140, LC343

Word Break Word Break - Medium 只要判断就可以，因此存boolean[]，O(N * N), O(N). class Solution { public boolean wordBreak(String s, List<String> w...

Posted by freeCookie🍪 on August 25, 2019

Leetcode - Unique BST

LC95，LC96

Unique BST 96. Unique Binary Search Trees 自底向上的dp解法，O(N * N), O(N). class Solution { public int numTrees(int n) { Map<Integer, In...

Posted by freeCookie🍪 on August 25, 2019

Leetcode - Ugly Number

LC263, LC264, LC313

Ugly Number Leetcode 的 ugly number，涉及到math，dp，heap。 Ugly Number 判断是不是ugly number，定义为质数因子只包括2，3，5的正数。可以迭代，可以递归。 public class Solution { publ...

Posted by freeCookie🍪 on August 25, 2019

Leetcode - Special Pattern

LC351, LC651, LC688, LC935

Special Pattern 有一些special pattern的限制的DP题。一般而言存一个map来表示可能的状态就可以。 351. Android Unlock Patterns 存了invalid path，并且利用对称性减少重复代码。是一个Backtrack问题。O(n!),...

Posted by freeCookie🍪 on August 25, 2019

Leetcode - Merge Intervals

Merge Intervals 一堆merge intervals的问题，基本上都是通过排序 + greedy来解决的。 56. Merge Intervals - M Merge intervals. 很多种解法，可以把start和end分别排序，找到end对应的starts，新建新的...

Posted by freeCookie🍪 on August 25, 2019

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