[Leetcode] 3Sum
摘要：
这道题目实际上有非常好的O（N^2)的解法。关键是利用了2sum的线性解法public class Solution { public List> threeSum(int[] nums) { List> res = new LinkedList>(); if(nu... 阅读全文
posted @ 2015-08-12 20:21 F_G 阅读(195) 评论(0) 推荐(0) 编辑
2015年8月12日 #
[Leetcode] Add Two Numbers
摘要：
数字表示为链表的格式，需要注意的几个地方：一、在计算过程当中要注意进位问题，刚开始的进位为0，后面进位要在计算过程当中进行更新。二、如果某个数字的list比较长，那么需要在最后将其加上三、最后如果进位不是零，说明需要额外增加一位代码如下： 1 /** 2 * Definition for sing... 阅读全文
posted @ 2015-08-12 20:15 F_G 阅读(165) 评论(0) 推荐(0) 编辑
[Leetcode] Two Sum
摘要：
1 import java.util.*; 2 3 public class Solution { 4 public int[] twoSum(int[] nums, int target) { 5 Map map = new HashMap(); 6 i... 阅读全文
posted @ 2015-08-12 20:12 F_G 阅读(167) 评论(0) 推荐(0) 编辑
[CTCI] Fobonacci Problem
摘要：
The problem is well known, so there is no need to repeat it!we can apply the iteration function f(n+1) = f(n)+f(n-1), however the time complexity is O... 阅读全文
posted @ 2015-08-12 20:04 F_G 阅读(151) 评论(0) 推荐(0) 编辑
[Leetcode] Subset I
摘要：
method 1: permutation !method 2: use integer and select element according to the bit in each integer. 阅读全文
posted @ 2015-08-12 17:12 F_G 阅读(102) 评论(0) 推荐(0) 编辑
[Leetcode] Permutation Sequence
摘要：
crute method is RE!! 阅读全文
posted @ 2015-08-12 17:09 F_G 阅读(96) 评论(0) 推荐(0) 编辑
[Leetcode] Next Permutation
摘要：
1. From the last index, we seach the first decrease order, such i,i+1 and num[i] 14532 -> 14235The last step is to change the order from 5 to 2 to be ... 阅读全文
posted @ 2015-08-12 16:56 F_G 阅读(145) 评论(0) 推荐(0) 编辑
[Leetcode] Permutations II
摘要：
The difference betweent Problem Permutation I and Permuation II lies in the duplicates elements may exist in the second one.For the first one , the en... 阅读全文
posted @ 2015-08-12 16:27 F_G 阅读(183) 评论(0) 推荐(0) 编辑
[Leetcode] Permutations
摘要：
I have two solutions for this problem, the first one is from the undergraduate stage, the second one is from the CTCI (permute string)The common point... 阅读全文
posted @ 2015-08-12 15:59 F_G 阅读(179) 评论(0) 推荐(0) 编辑
2015年8月11日 #
Mysql当中的on和where的区别
摘要：
MySQL当中的限制条件可以使用on或者where，两者在不同的情况下具有不同而意义如果是left join on，这里的on是对右表的限制，对左表没有限制如果是inner join on/where意思是一样的[1]http://www.jb51.net/article/39814.htm 阅读全文
posted @ 2015-08-11 23:33 F_G 阅读(515) 评论(0) 推荐(0) 编辑