Starry_1的博客

Given an array of integers, return indices of the two numbers such that they add up to a specific target.You may assume that each input would have exactly one solution, and you may not use the same ...

Implement int sqrt(int x).Compute and return the square root of x, where x is guaranteed to be a non-negative integer.Since the return type is an integer, the decimal digits are truncated and only...

Given two binary strings, return their sum (also a binary string).The input strings are both non-empty and contains only characters 1 or 0.public class AddBinarySolution { public String addBi...

Given a sorted linked list, delete all duplicates such that each element appear only once.public class Solution { public ListNode deleteDuplicates(ListNode head) { /** * 去除链表中的...

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?Note: Given n will be a positive...

Given a binary tree, check whether it is a mirror of itself (ie, symmetric around its center).For example, this binary tree [1,2,2,3,4,4,3] is symmetric/** * Definition for a binary tree node. ...

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.Note: A leaf is a node with no childre...

Given two sorted integer arrays nums1 and nums2, merge nums2 into nums1 as one sorted array.Note:The number of elements initialized in nums1 and nums2 are m and n respectively. You may assume tha...

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

Given an array where elements are sorted in ascending order, convert it to a height balanced BST.For this problem, a height-balanced binary tree is defined as a binary tree in which the depth of the...

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).Tips:题目说的很绕，说白了相当于树的层次遍历 public List<List<In...

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 b...

Given a string s consists of upper/lower-case alphabets and empty space characters ' ', return the length of last word in the string.If the last word does not exist, return 0.Note: A word is defin...

Given a non-empty array of digits representing a non-negative integer, plus one to the integer.The digits are stored such that the most significant digit is at the head of the list, and each element...

Given a 32-bit signed integer, reverse digits of an integer.Note:Assume we are dealing with an environment which could only store integers within the 32-bit signed integer range: [−231,  231 − 1]. ...

Write a function to find the longest common prefix string amongst an array of strings.If there is no common prefix, return an empty string "".Note:All given inputs are in lowercase letters a-z....

Given a sorted array nums, 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 by modifyi...

Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid.An input string is valid if:Open brackets must be closed by the same type of b...

Determine whether an integer is a palindrome. An integer is a palindrome when it reads the same backward as forward.字符串解法public class PalindromeNumberSolution { public boolean isPalindrome(int...

Roman numerals are represented by seven different symbols: I, V, X, L, C, D and M. For example, two is written as II in Roman numeral, just two one's added together. Twelve is written as, XII, whi...

Given an array nums and a value val, remove all instances of that value in-place and return the new length.Do not allocate extra space for another array, you must do this by modifying the input arra...

Implement strStr().Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.Clarification:What should we return when needle is an empty string? Thi...

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....

Given an integer array nums, find the contiguous subarray (containing at least one number) which has the largest sum and return its sum.Follow up:If you have figured out the O(n) solution, try cod...

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.public class MergeTwoSortedListsSolution { /** ...

Given a binary tree, find its minimum depth.The minimum depth is the number of nodes along the shortest path from the root node down to the nearest leaf node.Note: A leaf is a node with no childr...