Leetcode - 随笔分类(第12页) - neverlandly

Leetcode: Island Perimeter

摘要：You are given a map in form of a two-dimensional integer grid where 1 represents land and 0 represents water. Grid cells are connected horizontally/vertically (not diagonally). The grid is completely... 阅读全文

posted @ 2016-12-13 08:37 neverlandly 阅读(295) 评论(0) 推荐(0)

Leetcode: Can I Win

摘要：refer to https://discuss.leetcode.com/topic/68896/java-solution-using-hashmap-with-detailed-explanation After solving several "Game Playing" questions 阅读全文

posted @ 2016-12-13 07:59 neverlandly 阅读(1145) 评论(0) 推荐(0)

Leetcode: Repeated Substring Pattern

摘要：这道题应该没法用DP等解，只能brute force 或者 KMP（为深究） BruteForce, Best Solution for now except KMP 作为Encode String with Shortest Length的subproblem KMP解法未研究,https://d 阅读全文

posted @ 2016-12-13 04:43 neverlandly 阅读(730) 评论(0) 推荐(0)

Leetcode: Assign Cookies

摘要：Solution 1: Greedy, Time:O(nlogn) Just assign the cookies starting from the child with less greediness to maximize the number of happy children . Solu 阅读全文

posted @ 2016-12-13 02:23 neverlandly 阅读(332) 评论(0) 推荐(0)

Leetcode: 132 Pattern

摘要：我觉得这道题是hard，难点第一是要想到用stack，第二是要维护一个这样子的min-max序列：So at any time in the stack, non-overlapping Pairs are formed in descending order by their min value, 阅读全文

posted @ 2016-12-12 06:38 neverlandly 阅读(651) 评论(0) 推荐(0)

Leetcode: Arithmetic Slices II - Subsequence

摘要：参考了https://discuss.leetcode.com/topic/67413/detailed-explanation-for-java-o-n-2-solution 这道题DP思路还是能想出来，Time O(N^2), Space O(N^2) T(i, d), which denote 阅读全文

posted @ 2016-12-12 02:22 neverlandly 阅读(612) 评论(0) 推荐(0)

Leetcode: Minimum Moves to Equal Array Elements II

摘要：Just like meeting point problem, find the median elements in the array after sorting, so Solution 1: Sort, find the median: O(NlogN) Solution 2: Quick 阅读全文

posted @ 2016-12-10 02:59 neverlandly 阅读(407) 评论(0) 推荐(0)

Leetcode: 4Sum II

摘要：一开始想了一个O（n^3）, space O(N)的做法，后来发现还可以优化 Solution： time O(N^2), space O(N^2) 阅读全文

posted @ 2016-12-09 01:03 neverlandly 阅读(328) 评论(0) 推荐(0)

Leetcode: K-th Smallest in Lexicographical Order

摘要：第二遍做法：参考https://discuss.leetcode.com/topic/64624/concise-easy-to-understand-java-5ms-solution-with-explaination Actually this is a denary tree (each n 阅读全文

posted @ 2016-12-08 07:37 neverlandly 阅读(620) 评论(0) 推荐(0)

Leetcode: Minimum Number of Arrows to Burst Balloons

摘要：我的Greedy+Heap做法： Array按start moment升序sort，Heap里按end moment升序sort，一旦到Heap里结束时间最早的气球的end，就要扔arrow，这时在heap里的气球都会被引爆改进：因为一旦气球爆了的话，Heap里面的元素要全部清空，不需要知道Hea 阅读全文

posted @ 2016-12-08 04:33 neverlandly 阅读(474) 评论(0) 推荐(0)

Leetcode: Minimum Moves to Equal Array Elements

摘要：idea 1: suppose it takes y steps to equal each elements, then this equation stands: (min + y) * num.length == sum + (num.length-1)*y, where min + y is 阅读全文

posted @ 2016-12-08 00:48 neverlandly 阅读(386) 评论(0) 推荐(0)

Leetcode: Number of Boomerangs

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(494) 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(287) 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(607) 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(1422) 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(448) 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(762) 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(415) 评论(0) 推荐(0)

Leetcode: Strong Password Checker

摘要：refer to https://discuss.leetcode.com/topic/63854/o-n-java-solution-by-analyzing-changes-allowed-to-fix-each-problem http://www.cnblogs.com/grandyang/ 阅读全文

posted @ 2016-12-06 05:38 neverlandly 阅读(565) 评论(0) 推荐(0)

G 面经 && Leetcode: Longest Repeating Character Replacement

摘要：真是被这道题气死了，总是弄不对 The problem says that we can make at most k changes to the string (any character can be replaced with any other character). So, let's 阅读全文

posted @ 2016-12-05 13:58 neverlandly 阅读(437) 评论(0) 推荐(0)

随笔分类 - Leetcode