Ruizhi Ma's Blog

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Hello World, Hello Again!

Hey 十二月了，今天波士顿下雪了，我又像过去四五年那样随手写下“你顺手挽住火焰，化作漫天大雪”。第一次开通这个博客是5月2号，当时部署成功，兴奋了好久，然后陆陆续续刷题，并且把思路，想法，代码都push上来，尽管很多都是借鉴的其他人的。当时相信一步一步来，从easy到medium，一道一道写，不会写就抄，总能积少成多。中间的确沉沦过一段时间，各种事情冲击让自己挣扎，迷茫。好在，在19年最...

Posted by Ruizhi Ma on December 1, 2019

Problem 12

Integer to Roman

问题描述 https://leetcode.com/problems/integer-to-roman/ 解决思路用int数组value保存数字，用String数组保存对应的罗马数字，若num大于value的值，则将其从num中减去，并且将对应的罗马数字通过stringBuilder加进去。代码（07/13） class Solution { public String in...

Posted by Ruizhi Ma on November 30, 2019

Problem 106

Construct Binary Tree from Inorder and Postorder Traversal

代码 /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ class Solution { ...

Posted by Ruizhi Ma on August 24, 2019

Problem 105

Construct Binary Tree from Preorder and Inorder Traversal

问题描述解决思路问题解惑代码 /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ c...

Posted by Ruizhi Ma on August 23, 2019

Problem 177

Nth Highest Salary

问题描述 https://leetcode.com/problems/nth-highest-salary/ 代码 CREATE FUNCTION getNthHighestSalary(N INT) RETURNS INT BEGIN DECLARE m INT; SET m = n - 1; RETURN ( # Write your MySQL query stat...

Posted by Ruizhi Ma on August 22, 2019

Problem 109

问题描述解决思路问题解惑代码 /** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode(int x) { val = x; } * } */ /** * Definition for a ...

Posted by Ruizhi Ma on August 21, 2019

Problem 103

Zigzag Level Order

问题描述解决思路问题解惑代码 /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) { val = x; } * } */ c...

Posted by Ruizhi Ma on August 21, 2019

Problem 110

Balanced Binary Tree

问题描述题目看链接：https://leetcode.com/problems/balanced-binary-tree/ 解决思路递归左右子树，比较两边之差即可代码 /** * Definition for a binary tree node. * public class TreeNode { * int val; * TreeNode left; ...

Posted by Ruizhi Ma on August 19, 2019

Problem 108

Convert Sorted Array to Binary Search Tree

问题描述 https://leetcode.com/problems/convert-sorted-array-to-binary-search-tree/ 解决思路二分法找中间节点放入数组，递归解决。代码 /** * Definition for a binary tree node. * public class TreeNode { * int val; * ...