摘要：
Corner cases!class Solution {public: ListNode *deleteDuplicates(ListNode *head) { if (!head) return head; if (!head->next) return hea... 阅读全文
posted @ 2014-08-03 07:04
Tonix
阅读(171)
评论(0)
推荐(0)
摘要：
Nothing special. A typical list manipulation problem.class Solution {public: ListNode *partition(ListNode *head, int x) { if (!head) return ... 阅读全文
posted @ 2014-08-03 06:39
Tonix
阅读(131)
评论(0)
推荐(0)
摘要：
It is all about corner cases.class Solution {public: vector retv; bool isValid(string &sub) { unsigned cnt = sub.length(); if (... 阅读全文
posted @ 2014-08-02 11:07
Tonix
阅读(182)
评论(0)
推荐(0)
摘要：
Lexicographicallyalgorithms:1. Iterate array from back to front, and find the first decreasing point: 1,2,4,3 -- 42. Iterate array from back to front,... 阅读全文
posted @ 2014-08-02 03:42
Tonix
阅读(141)
评论(0)
推荐(0)
摘要：
First I implemented it by QuickSort, but got a TLE:class Solution {public: struct Pair { Pair(ListNode *pS, ListNode *pE) : pStart(pS), p... 阅读全文
posted @ 2014-08-02 03:19
Tonix
阅读(146)
评论(0)
推荐(0)
摘要：
Greedy, Greedy, Greedy.. It is all about maximum interval update.One trick is, we start looping over each element from the one nearest to end to farth... 阅读全文
posted @ 2014-08-01 12:07
Tonix
阅读(125)
评论(0)
推荐(0)
摘要：
A simulation problem. We simple walk through all reachable items until we cannot proceed.class Solution {public: bool canJump(int A[], int n) { ... 阅读全文
posted @ 2014-08-01 11:11
Tonix
阅读(114)
评论(0)
推荐(0)
摘要：
Next time you see a numeric problem has a too straightforward solution, think about optimized one.Like this one: recursion\iteration is tooo slow. SoD... 阅读全文
posted @ 2014-08-01 05:09
Tonix
阅读(158)
评论(0)
推荐(0)
摘要：
Just corner case..class Solution {public: ListNode *reverseBetween(ListNode *head, int m, int n) { if(m == n) return head; ListNode *... 阅读全文
posted @ 2014-07-31 08:06
Tonix
阅读(126)
评论(0)
推荐(0)
摘要：
I fell in a deadloop, and didn't see the actual recursion pattern.Reference:http://fisherlei.blogspot.com/2013/03/leetcode-unique-binary-search-trees-... 阅读全文
posted @ 2014-07-31 07:19
Tonix
阅读(98)
评论(0)
推荐(0)
摘要：
The only difference with version I is: one number can only be used once:class Solution {public: vector > ret; struct Rec { Rec() : sum... 阅读全文
posted @ 2014-07-31 03:40
Tonix
阅读(108)
评论(0)
推荐(0)
摘要：
A very interesting numeric problem. It involves a lot tricks.Linear search (by +\-) is not feasible - too slow. So binary search is a good idea. Also ... 阅读全文
posted @ 2014-07-29 12:25
Tonix
阅读(150)
评论(0)
推荐(0)
摘要：
Similar with "Longest Consecutive Sequence". Another usage to hashset.Take care of corner cases!class Solution {public: int firstMissingPositive(in... 阅读全文
posted @ 2014-07-28 12:27
Tonix
阅读(176)
评论(0)
推荐(0)
摘要：
A BFS usage.class Solution {public: UndirectedGraphNode *cloneGraph(UndirectedGraphNode *node) { if (!node) return NULL; UndirectedGr... 阅读全文
posted @ 2014-07-28 11:49
Tonix
阅读(132)
评论(0)
推荐(0)
摘要：
Similar with "Climb stairs" but with more restrictions.// Ref: http://yucoding.blogspot.com/2013/01/leetcode-question-26-decode-ways.htmlclass Solu... 阅读全文
posted @ 2014-07-28 08:25
Tonix
阅读(132)
评论(0)
推荐(0)
摘要：
Typical recurrsion\DFS problem. Just take care of memory use.class Solution {public: vector> ret; void go(int currMaxN, int currK, int k, unorde... 阅读全文
posted @ 2014-07-28 06:12
Tonix
阅读(154)
评论(0)
推荐(0)
摘要：
Compared with I version, the tree could be incomplete. The only difference is that, we connect current node's child to next non-childrenless' node's f... 阅读全文
posted @ 2014-07-26 15:01
Tonix
阅读(150)
评论(0)
推荐(0)
摘要：
Flood-Fill. BFS. But there's a trick. If we fill surrounded region directly, extra bookkeeping cost is needed - because we don't know whether that reg... 阅读全文
posted @ 2014-07-26 14:09
Tonix
阅读(190)
评论(0)
推荐(0)
摘要：
Comparison-based sorting takes O(nlgn), so hashset is a good idea. After keeping records of all numbers in the hashset, you start checking each number... 阅读全文
posted @ 2014-07-25 01:14
Tonix
阅读(212)
评论(0)
推荐(0)
摘要：
Nothing to hard to think. Just take care of boundary conditions.class Solution {public: string convert(string s, int nRows) { if(s.empty() |... 阅读全文
posted @ 2014-07-23 12:54
Tonix
阅读(168)
评论(0)
推荐(0)
浙公网安备 33010602011771号