starcroce-优快云博客

原创 LeetCode - Permutations

Given a collection of numbers, return all possible permutations.For example,[1,2,3] have the following permutations:[1,2,3], [1,3,2], [2,1,3], [2,3,1], [3,1,2], and [3,2,1].http://oj.leetcode.

2014-01-30 06:00:44 578

原创 LeetCode - Binary Tree Level Order Traversal II

Given a binary tree, return the bottom-up level order traversal of its nodes' values. (ie, from left to right, level by level from leaf to root).For example:Given binary tree {3,9,20,#,#,15,7},

2014-01-30 05:22:47 582

原创 LeetCode - Gray Code

The gray code is a binary numeral system where two successive values differ in only one bit.Given a non-negative integer n representing the total number of bits in the code, print the sequence of gr

2014-01-30 04:56:28 569

原创 LeetCode - Best Time to Buy and Sell Stock

Say you have an array for which the ith element is the price of a given stock on day i.If you were only permitted to complete at most one transaction (ie, buy one and sell one share of the stock), d

2014-01-30 04:44:14 722

原创 LeetCode - Single Number II

Given an array of integers, every element appears three times except for one. Find that single one.Note:Your algorithm should have a linear runtime complexity. Could you implement it without using

2014-01-30 04:34:29 718

原创 LeetCode - Balanced Binary Tree

Given a binary tree, determine if it is height-balanced.For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the two subtrees of every node never differ

2014-01-30 04:07:05 777

原创 LeetCode - Integer to Roman

Given an integer, convert it to a roman numeral.Input is guaranteed to be within the range from 1 to 3999.http://oj.leetcode.com/problems/integer-to-roman/Solution:First let's review the

2014-01-30 03:56:44 527

原创 LeetCode - Pascal's Triangle

Given numRows, generate the first numRows of Pascal's triangle.For example, given numRows = 5,Return[ [1], [1,1], [1,2,1], [1,3,3,1], [1,4,6,4,1]]http://oj.leetcode.com/probl

2014-01-18 02:51:46 507

原创 LeetCode - Swap Nodes in Pairs

Given a linked list, swap every two adjacent nodes and return its head.For example,Given 1->2->3->4, you should return the list as 2->1->4->3.Your algorithm should use only constant space. You m

2014-01-18 02:18:07 499

原创 LeetCode - Merge Sorted Array

Given two sorted integer arrays A and B, merge B into A as one sorted array.Note: You may assume that A has enough space to hold additional elements from B. The number of elements initialized in A

2014-01-16 03:51:43 558

原创 LeetCode - Convert Sorted Array to Binary Search Tree

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.http://oj.leetcode.com/problems/convert-sorted-array-to-binary-search-tree/Solution:Obvious

2014-01-16 03:46:01 553

原创 LeetCode - Merge Two Sorted Lists

Merge two sorted linked lists and return it as a new list. The new list should be made by splicing together the nodes of the first two lists.http://oj.leetcode.com/problems/merge-two-sorted-lists/

2014-01-16 02:35:48 781

原创 LeetCode - Roman to Integer

Given a roman numeral, convert it to an integer.Input is guaranteed to be within the range from 1 to 3999.http://oj.leetcode.com/problems/roman-to-integer/Solution:First thing is to have

2014-01-16 02:08:24 479

原创 LeetCode - Symmetric Tree

Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).For example, this binary tree is symmetric: 1 / \ 2 2 / \ / \3 4 4 3But the followin

2014-01-16 01:51:39 481

原创 LeetCode - Maximum Subarray

Find the contiguous subarray within an array (containing at least one number) which has the largest sum.For example, given the array [−2,1,−3,4,−1,2,1,−5,4], the contiguous subarray [4,−1,2,1] has t

2014-01-15 11:56:47 549

原创 LeetCode - Climbing Stairs

You are climbing a stair case. It takes n steps to reach to the top.Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top?http://oj.leetcode.com/problems/

2014-01-15 10:41:40 479

原创 LeetCode - Remove Element

Given an array and a value, remove all instances of that value in place and return the new length.The order of elements can be changed. It doesn't matter what you leave beyond the new length.htt

2014-01-14 04:31:18 464

原创 LeetCode - Remove Duplicates from Sorted Array

Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length.Do not allocate extra space for another array, you must do this in place with c

2014-01-14 04:03:21 482

原创 LeetCode - Binary Tree Preorder Traversal

Given a binary tree, return the preorder traversal of its nodes' values.For example:Given binary tree {1,#,2,3}, 1 \ 2 / 3return [1,2,3].http://oj.leetcode.com/problems

2014-01-14 03:12:42 541

原创 LeetCode - Binary Tree Inorder Traversal

Given a binary tree, return the inorder traversal of its nodes' values.For example:Given binary tree {1,#,2,3}, 1 \ 2 / 3return [1,3,2].Note: Recursive solution is tri

2014-01-14 01:23:09 662

原创 LeetCode - Populating Next Right Pointers in Each Node

Given a binary tree struct TreeLinkNode { TreeLinkNode *left; TreeLinkNode *right; TreeLinkNode *next; }Populate each next pointer to point to its next right node. If t

2014-01-14 00:46:00 605

原创 LeetCode - Search Insert Position

Given a sorted array and a target value, return the index if the target is found. If not, return the index where it would be if it were inserted in order.You may assume no duplicates in the array. H

2014-01-13 15:49:01 983

原创 LeetCode - Remove Duplicates from Sorted List

Given a sorted linked list, delete all duplicates such that each element appear only once.For example, given 1->1->2, return 1->2; given 1->1->2->3->3, return 1->2->3.http://oj.leetcode.com/proble

2014-01-13 15:37:45 584

原创 LeetCode - Linked List Cycle

Given a linked list, determine if it has a cycle in it.http://oj.leetcode.com/problems/linked-list-cycle/Solution:Very popular problem. Use two pointer, p1 move two steps every time and p2

2014-01-13 15:31:34 471

原创 LeetCode - Best Time to Buy and Sell Stock II

Say you have an array for which the ith element is the price of a given stock on day i.Design an algorithm to find the maximum profit. You may complete as many transactions as you like (ie, buy one

2014-01-13 15:27:10 536

原创 LeetCode - Unique Binary Search Trees

Given n, how many structurally unique BST's (binary search trees) that store values 1...n?Given n = 3, there are a total of 5 unique BST's. 1 3 3 2 1 \ /

2014-01-13 14:36:10 424

原创 LeetCode - Reverse Integer

Reverse digits of an integer.Example1: x = 123, return 321; x = -123, return -321http://oj.leetcode.com/problems/reverse-integer/Solution:Start from the last digit which is the input % 10, t

2014-01-13 14:02:07 465

原创 LeetCode - Same Tree

Given two binary trees, write a function to check if they are equal or not.Two binary trees are considered equal if they are structurally identical and the nodes have the same value.http://oj.le

2014-01-13 13:46:00 536

原创 LeetCode - Maximum Depth of Binary Tree

Given a binary tree, find its maximum depth.The maximum depth is the number of nodes along the longest path from the root node down to the farthest leaf node. http://oj.leetcode.com/problems/max

2014-01-13 13:40:49 481

原创 LeetCode - Single Number

Given an array of integers, every element appears twice except for one. Find that single one.Note:Your algorithm should have a linear runtime complexity. Could you implement it without using e

2014-01-13 13:33:57 524

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