My LeetCode Journey

https://leetcode.com/problems/valid-sudoku/description/ At first "446 / 501  test cases passed.", after using Console.Write output the whole test case and help me to debug the issue. Bug was found and fixed.

https://leetcode.com/problems/regular-expression-matching/description/ Use the Recursion method, so the performance, hurt a bit.

https://leetcode.com/problems/median-of-two-sorted-arrays/description/

https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/description/

https://leetcode.com/problems/lowest-common-ancestor-of-a-binary-tree/description/ More information could be found here https://www.geeksforgeeks.org/lowest-common-ancestor-in-a-binary-tree-set-2-using-parent-pointer/

https://leetcode.com/problems/generate-parentheses/description/

https://leetcode.com/problems/linked-list-cycle/description/

https://leetcode.com/problems/binary-tree-maximum-path-sum/description/ They made the problem more tricky by allowing negative Node Value and two leg "path extensions"

https://leetcode.com/problems/maximum-depth-of-binary-tree/description/ Walk in the park...

https://leetcode.com/problems/unique-binary-search-trees/description/ public class Solution {     int[] table = new int[200];     public int NumTrees(int n) {                 for (int i=0; i<200; i++)             table[i]=-1;         table[0]=1; table[1]=1;         return catalan(n);     }         int catalan(int n) {         int res = 0;         int n1=0; int n2=0;                 // Base case         if (n <= 1) {             return 1;         }                 if(table[n]!=-1)             return table[n];                 for (int i = 0; i ...

https://leetcode.com/problems/validate-binary-search-tree/description/

https://leetcode.com/problems/binary-tree-level-order-traversal/description/

https://leetcode.com/problems/binary-tree-inorder-traversal/description/

https://leetcode.com/problems/longest-substring-without-repeating-characters/description/ Finished the problem with best performance.

https://leetcode.com/problems/valid-parentheses/description/ Their bloody test case used test string more than 1000 characters long!

https://leetcode.com/problems/add-two-numbers/discuss/?page=72 But failing one of its test cases, tested the same test case locally but succeeded! So you cannot really believe the LeetCode online judge. After more digging, it turned out the test case they put together included value outside the range of the LONG data type, you have implemented addition without using the addition of integers!!!!!

Started with Jagged Array solution failed some made up test cases-due to Memory Limit Exceeded . Only passed the test cases after removing the usage of the Jagged Array. Doh. https://leetcode.com/problems/two-sum/description/

https://leetcode.com/problems/insertion-sort-list/description/

https://leetcode.com/problems/n-queens/description/

https://leetcode.com/problems/water-and-jug-problem/description/ Time Exceeded Limit on test case " 22003, 31237, 1"... These guys obviously tried too hard to make people's submission fail.

https://leetcode.com/problems/best-time-to-buy-and-sell-stock/description/