jianchao_li
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jianchao_li
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个人介绍
热爱人工智能、机器学习和算法；截至2018年1月2日，LeetCode用户Most Reputation排名第2（https://discuss.leetcode.com/users?section=sort-reputation）
擅长的技术
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发表了文章 2015-07-06
[LeetCode] Substring with Concatenation of All Words
I think the following code is self-explanatory enough. We use an unordered_map counts to record the expected times of each word and another unordered_map seento record the times we have seen.
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发表了文章 2015-07-06
[LeetCode] Insert Interval
By far the best solution I have seen is of O(n) time (some solutions claim to be of O(logn) turns out to be O(n)).
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发表了文章 2015-07-06
[LeetCode] Reverse Lists
Well, since the head pointer may also be modified, we create a new_head that points to it to facilitate the reverse process.
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发表了文章 2015-07-06
[LeetCode] Reverse Nodes in k-Group
Well, since the head pointer may also be modified, we create a new_head that points to it to facilitate the reverse process.
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发表了文章 2015-07-06
[LeetCode] Swap Nodes in Pairs
Well, since the head pointer may also been modified, we create a new_head that points to it to facilitate the swapping process.
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发表了文章 2015-07-06
[LintCode] 通配符查询
动态规划： 1 class Solution { 2 public: 3 /** 4 * @param s: A string 5 * @param p: A string includes "?" and "*" 6 * @ret...
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发表了文章 2015-07-06
[LeetCode] Wildcard Matching
Well, so many people has tried to solve this problem using DP. And almost all of them get TLE (if you see a C++ DP solution that gets accepted, please let me know ^_^).
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发表了文章 2015-07-06
[LeetCode] Merge k Sorted Lists
Well, the idea of this problem is actually very sample --- keep merging the unmerged lists in lists until there is exactly one list remained.
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发表了文章 2015-07-05
[LintCode] 正则表达式匹配
1 class Solution { 2 public: 3 /** 4 * @param s: A string 5 * @param p: A string includes ".
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发表了文章 2015-07-05
[LeetCode] Regular Expression Matching
This problem has a typical solution using Dynamic Programming. We define the state P[i][j] to be true if s[0.
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发表了文章 2015-07-04
[LeetCode] Binary Tree Zigzag Level Order Traversal
To be honest, I do not know whether this problem is designed to let you use stacks. Anyway, I don't. Here are my codes, both BFS and DFS version.
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发表了文章 2015-07-03
[LintCode] 两个排序数组的中位数
1 class Solution { 2 public: 3 /** 4 * @param A: An integer array. 5 * @param B: An integer array.
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发表了文章 2015-07-03
[LeetCode] Median of Two Sorted Arrays
This link has a very concise and fast solution based on binary search. Spend some time reading it and make sure you understand it.
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发表了文章 2015-07-03
[LeetCode] Word Ladder II
This is a tough problem! I read some solutions from the web. This link provides a one-end BFS solution.
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发表了文章 2015-07-02
[LeetCode] Edit Distance
This is a classic problem of Dynamic Programming. We define the state dp[i][j] to be the minimum number of operations to convert word1[0.
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发表了文章 2015-07-02
[LeetCode] Merge Intervals
The idea to solve this problem is to first sort the intervals according to their start field and then scan the intervals from head to tail and merge those that overlap.
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发表了文章 2015-07-02
[LeetCode] Merge Sorted Array
A classic subroutine of merge sort. Just merge the elements from back to forth. Keep a pointer for the merged position of the element and two other po...
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发表了文章 2015-07-02
[LeetCode] Word Break
The typical solution to this problem is to use Dynamic Programming. The state dp[i] represents whether s[0.
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发表了文章 2015-07-02
[LeetCode] Kth Smallest Element in a BST
This link suggests a concise C++ recursive solution. The original code may be hard to understand at first and I have rewritten the code below.
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发表了文章 2015-07-01
[LeetCode] N-Queens II
If you have solved the N-Queens problem, this one can be solved in a similar manner. Starting from the first row, we try each of its columns.
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发表了文章 2015-07-01
[LeetCode] N-Queens
The idea is to use backtracking. In fact, the code below uses DFS, which involves backtracking in a recursive manner.
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发表了文章 2015-07-01
[LintCode] O(1)检测2的幂次
1 class Solution { 2 public: 3 /* 4 * @param n: An integer 5 * @return: True or false 6 */ 7 bool checkPowerOf2(...
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发表了文章 2015-06-30
[hihoCoder] KMP算法
Each time we find a match, increase the global counter by 1. For KMP, algorithm, you may refer to the following links which have nice explanations.
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发表了文章 2015-06-30
[LeetCode] Majority Element II
Well, this problem becomes a little trickier since there may be more than one majority element. But, there can be at most two of them.
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发表了文章 2015-06-30
[LeetCode] Majority Element
Well, if you have got this problem accepted, you may have noticed that there are 7 suggested solutions for this problem.
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发表了文章 2015-06-30
[LintCode] 最长单词
1 class Solution { 2 public: 3 /** 4 * @param dictionary: a vector of strings 5 * @return: a vector of strings 6 */ ...
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发表了文章 2015-06-29
[LintCode] 空格替换
1 class Solution { 2 public: 3 /** 4 * @param string: An array of Char 5 * @param length: The true length of the string 6 ...
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发表了文章 2015-06-29
[LintCode] 字符串查找
暴力解法（O(mn)）： 1 class Solution { 2 public: 3 /** 4 * Returns a index to the first occurrence of target in source, 5 * or -1 if target is not part of source.
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发表了文章 2015-06-29
[LintCode] 链表插入排序
1 /** 2 * Definition of ListNode 3 * class ListNode { 4 * public: 5 * int val; 6 * ListNode *next; 7 * ListNode(int v...
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发表了文章 2015-06-29
[LeetCode] Insertion Sort List
Well, life gets difficult pretty soon whenever the same operation on array is transferred to linked list.
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发表了文章 2015-06-29
[LintCode] 合并排序数组II
1 class Solution { 2 public: 3 /** 4 * @param A: sorted integer array A which has m elements, 5 * but size of A is...
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发表了文章 2015-06-29
[LintCode] 二叉树的后序遍历
The recursive solution is trivial and I omit it here. Iterative Solution using Stack (O(n) time and O(n) space): 1 /** 2 * Definition of TreeN...
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发表了文章 2015-06-29
[LintCode] 合并排序数组
A subroutine of merge sort. 1 class Solution { 2 public: 3 /** 4 * @param A and B: sorted integer array A and B.
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发表了文章 2015-06-29
[LintCode] 二叉树的中序遍历
The recursive solution is trivial and I omit it here. Iterative Solution using Stack (O(n) time and O(n) space): 1 /** 2 * Definition of TreeN...
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发表了文章 2015-06-29
[LintCode] 二叉树的前序遍历
The recursive solution is trivial and I omit it here. Iterative Solution using Stack (O(n) time and O(n) space): 1 /** 2 * Definition of TreeN...
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发表了文章 2015-06-29
[LintCode] 最长上升子序列
动态规划： lis[i] = max_{j = 0, 1, ..., i - 1, nums[j] < nums[i]} lis[j] + 1 1 class Solution { 2 public: 3 /** 4 * @param nums: The in...
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发表了文章 2015-06-29
[LintCode] 最长公共前缀
1 class Solution { 2 public: 3 /** 4 * @param strs: A list of strings 5 * @return: The longest common prefix 6 */ ...
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发表了文章 2015-06-29
[LintCode] A + B 问题
Bit-by-Bit summation: 1 class Solution { 2 public: 3 /* 4 * @param a: The first integer 5 * @param b: The second integer 6...
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发表了文章 2015-06-28
[hihoCoder] 拓扑排序·一
The hints of the problem has given detailed information to implement the topological sorting algorithm.
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发表了文章 2015-06-28
[LintCode] 拓扑排序
BFS: 1 /** 2 * Definition for Directed graph. 3 * struct DirectedGraphNode { 4 * int label; 5 * vector neighbors; 6 * D...
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发表了文章 2015-06-28
[LintCode] 第k大元素
基于快速排序： 1 class Solution { 2 public: 3 /* 4 * param k : description of k 5 * param nums : description of array and index 0 ~...
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发表了文章 2015-06-28
[LintCode] 最小路径和
1 class Solution { 2 public: 3 /** 4 * @param grid: a list of lists of integers. 5 * @return: An integer, minimizes the sum o...
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发表了文章 2015-06-28
[LeetCode] Factorial Trailing Zeros
Well, to compute the number of trailing zeros, we need to first think clear about what will generate a trailing 0? Obviously, a number multiplied by 10 will have a trailing 0 added to it.
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发表了文章 2015-06-28
[LintCode] 尾部的零
1 class Solution { 2 public: 3 // param n : description of n 4 // return: description of return 5 long long trailingZeros(lon...
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发表了文章 2015-06-28
[LeetCode] Length of Last Word
Well, the basic idea is very simple. Start from the tail of s and move backwards to find the first non-space character.
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发表了文章 2015-06-28
[LintCode] 最后一个单词的长度
1 class Solution { 2 public: 3 /** 4 * @param s A string 5 * @return the length of last word 6 */ 7 int lengthOf...
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发表了文章 2015-06-28
[LintCode] 有效回文串
1 class Solution { 2 public: 3 /** 4 * @param s A string 5 * @return Whether the string is a valid palindrome 6 */ 7...
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发表了文章 2015-06-28
[LintCode] 有效的括号序列
1 class Solution { 2 public: 3 /** 4 * @param s A string 5 * @return whether the string is a valid parentheses 6 */ ...
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发表了文章 2015-06-28
[LintCode] 翻转二叉树
递归实现： 1 /** 2 * Definition of TreeNode: 3 * class TreeNode { 4 * public: 5 * int val; 6 * TreeNode *left, *right; 7 * ...
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发表了文章 2015-06-28
[LintCode] 带最小值操作的栈
1 class MinStack { 2 public: 3 MinStack() { 4 // do initialization if necessary 5 } 6 7 void push(int number) { ...
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发表了文章
2018-01-02
Jianchao's Blog is gonna to be moved to Yunqi
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发表了文章
2016-09-10
[LeetCode] Sum of Two Integers
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发表了文章
2016-08-14
[LeetCode] Ransom Note
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发表了文章
2015-12-03
[LeetCode] Sparse Matrix Multiplication
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发表了文章
2015-11-23
[LeetCode] Range Sum Query - Mutable
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发表了文章
2015-11-20
[LeetCode] Additive Number
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发表了文章
2015-11-14
[LeetCode] Number of Islands II
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发表了文章
2015-11-12
[LeetCode] Range Sum Query 2D - Immutable
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发表了文章
2015-11-10
[LeetCode] Range Sum Query - Immutable
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发表了文章
2015-11-08
[LeetCode] Smallest Rectangle Enclosing Black Pixels
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发表了文章
2015-11-05
[LeetCode] Remove Invalid Parentheses
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发表了文章
2015-11-03
[LeetCode] Longest Increasing Subsequence
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发表了文章
2015-10-31
[LeetCode] Bulls and Cows
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发表了文章
2015-10-30
[LeetCode] Binary Tree Longest Consecutive Sequence
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发表了文章
2015-10-30
[LeetCode] Serialize and Deserialize Binary Tree
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发表了文章
2015-10-22
[LeetCode] Best Meeting Point
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发表了文章
2015-10-19
[LeetCode] Find Median from Data Stream
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发表了文章
2015-10-17
[LeetCode] Flip Game II
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发表了文章
2015-10-15
[LeetCode] Flip Game
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发表了文章
2015-10-13
[LeetCode] Nim Game
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