Problem: Sort a linked list using insertion sort. The node of the linked list is defined as: /** * Definition for singly-linked list. * struct ListNode { * int val; * ListNode *next; * ListNode(int x) : val(x), next(NULL) {} * }; */ The insertion sor…

Sort a linked list using insertion sort. Subscribe to see which companies asked this question 解答 对于链表的插入排序,用tmp_tail遍历链表,每次的待插入数是tmp_tail->next的元素,待插入数必须从头开始比较,当然从头开始比较时要注意处理待排序数小于或等于链表首元素的情况,因为插入在链表的首元素之前与一般情况的插入不同,而如果待插入数插入在它之前的数列中,则用于遍历链表的指针tmp_ta…

Problem Link: http://oj.leetcode.com/problems/interleaving-string/ Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2. For example, Given: s1 = "aabcc", s2 = "dbbca", When s3 = "aadbbcbcac", return t…

Problem link: http://oj.leetcode.com/problems/reverse-words-in-a-string/ Given an input string, reverse the string word by word. For example, Given s = "the sky is blue", return "blue is sky the". LeetCode OJ supports Python now! The s…

Sort a linked list using insertion sort. 用插入排序来排序一个list,额, 我写的好麻烦啊, debug了好久,至少提交了5次...写吐了快,先贴代码,写的也好乱啊: class Solution { public: ListNode* insertionSortList(ListNode* hed) { if (hed == NULL) return NULL; head = hed; ListNode * insertPosPrev; ListNod…

Problem link: http://oj.leetcode.com/problems/reorder-list/ I think this problem should be a difficult problem, since it requries three classic algorithms on the single-linked list: Split a single-linked list into halves Reverse a single-linked list…

Problem Link: https://oj.leetcode.com/problems/validate-binary-search-tree/ We inorder-traverse the tree, and for each node we check if current_node.val > prev_node.val. The code is as follows. # Definition for a binary tree node # class TreeNode: #…

Problem Link: https://oj.leetcode.com/problems/recover-binary-search-tree/ We know that the inorder traversal of a binary search tree should be a sorted array. Therefore, we can compare each node with its previous node in the inorder to find the two…

Problem Link: https://oj.leetcode.com/problems/same-tree/ The following recursive version is accepted but the iterative one is not accepted... # Definition for a binary tree node # class TreeNode: # def __init__(self, x): # self.val = x # self.left =…

Problem Link: https://oj.leetcode.com/problems/symmetric-tree/ To solve the problem, we can traverse the tree level by level. For each level, we construct an array of values of the length 2^depth, and check if this array is symmetric. The tree is sym…