Gray Code
Description The description of this problem is very vague. It is even unclear what is the gray code with 3 bits. What is worse, according to wikipedia, there do exist various ways of defining gray code. With some “guessing” work,...
Balanced Binary Tree
Description https://oj.leetcode.com/problems/balanced-binary-tree/ Difficulty: 1.0/5.0 star Solution /** * Definition for binary tree * struct TreeNode { * int val; * TreeNode *left; * TreeNode *right; * TreeNode(int x) : val(x), left(NULL), right(NULL) {} * }; */ class Solution { public:...
Remove Element
Description https://oj.leetcode.com/problems/remove-element/ Difficulty: 1.5/5.0 star Analysis and solution class Solution { public: int removeElement(int A[], int n, int elem) { queue<int>emptySlot; int numRemove = 0; for (int i = 0; i < n; ++ i){ if (A[i] == elem){ emptySlot.push(i);...
Merge Two Sorted Lists
Description https://oj.leetcode.com/problems/merge-two-sorted-lists/ Difficulty: 0.5/5.0 star Solution /** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ class Solution { public: ListNode *mergeTwoLists(ListNode *l1, ListNode...
Maximum Subarray
Description https://oj.leetcode.com/problems/maximum-subarray/ Difficulty: 1.0/5.0 star Related problem: https://oj.leetcode.com/problems/maximum-product-subarray/ Resource: http://en.wikipedia.org/wiki/Kadane%27s_Algorithm Analysis This is actually a 1-D DP problem. Supposed that indicates the maximum summation you can get with element involved, the maxSum[i] = max(A[i], maxSum[i] + A[i]) When it comes...