2016 年 12月 7 日随笔档案 - neverlandly

2016年12月7日

摘要： Solution: Use HashTable, Time: O(N^2), Space: O(N) 我的：注意14行是有value个重复distance，表示有value个点，他们跟指定点距离都是distance，需要选取2个做permutation, 所以是value * (value-1) 别阅读全文

posted @ 2016-12-07 13:51 neverlandly 阅读(496) 评论(0) 推荐(0)

Leetcode: Arranging Coins

摘要： count is the # of level, sum is the accumulated coins Better Solution: Binary Search, 因为怕溢出，所以(1+m)m/2表示成了line6那种样子. 用m去估计最后返回的row 阅读全文

posted @ 2016-12-07 13:44 neverlandly 阅读(291) 评论(0) 推荐(0)

Leetcode: Path Sum III

摘要： Add the prefix sum to the hashMap, and check along path if hashMap.contains(pathSum+cur.val-target); My Solution 一个更简洁的solution: using HashMap to stor 阅读全文

posted @ 2016-12-07 12:17 neverlandly 阅读(612) 评论(0) 推荐(0)

Leetcode: All O`one Data Structure

摘要： Solution: O(1) time complexity 解题思路主要参考了网友ivancjw的帖子，数据结构参考了https://discuss.leetcode.com/topic/65634/java-ac-all-strict-o-1-not-average-o-1-easy-to-re 阅读全文

posted @ 2016-12-07 09:09 neverlandly 阅读(1428) 评论(0) 推荐(0)

Leetcode: Find Right Interval

摘要： Solution 1: TreeMap, Time complexity: O(NlogN) 像这种在一个集合里面寻找有没有比某个数小的数，一般要么treeMap要么treeSet。Interval的题经常需要用treeMap, Data Stream as Disjoint Intervals 就阅读全文

posted @ 2016-12-07 04:53 neverlandly 阅读(449) 评论(0) 推荐(0)

Leetcode: Non-overlapping Intervals

摘要： Actually, the problem is the same as "Given a collection of intervals, find the maximum number of intervals that are non-overlapping." (the classic Gr 阅读全文

posted @ 2016-12-07 01:28 neverlandly 阅读(765) 评论(0) 推荐(0)

Leetcode: Number of Segments in a String

摘要：用split() 不用API, better solution, O(N) time O(1) space 阅读全文

posted @ 2016-12-07 00:36 neverlandly 阅读(417) 评论(0) 推荐(0)