tterminator的专栏

一、问题描述How would you print just the 10th line of a file?For example, assume that file.txt has the following content:Line 1 Line 2 Line 3 Line 4 Line 5 Line 6 Line 7 Line 8 Line 9 Line 10Your sc

一、问题描述 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

一、问题描述 Given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maximum jump length at that position.

一、问题描述 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

一、问题描述 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

一、问题描述 Given n non-negative integers a1, a2, ..., an, where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (

一、问题描述 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

一、问题描述 Given an integer n, generate a square matrix filled with elements from 1 to n2 in spiral order. For example, Given n = 3, You should return the following matrix: [ [ 1, 2, 3 ], [ 8

一、问题描述 Given a matrix of m x n elements (m rows, n columns), return all elements of the matrix in spiral order. For example, Given the following matrix: [ [ 1, 2, 3 ], [ 4, 5, 6 ], [ 7, 8

一、问题描述 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] ] 二、问题分析 从上往下

一、问题描述 Given an index k, return the kth row of the Pascal's triangle. For example, given k = 3, Return [1,3,3,1]. Note: Could you optimize your algorithm to use only O(k) extra space? 二、

一、问题描述（二叉树中序遍历） Given a binary tree, return the inorder traversal of its nodes' values. For example: Given binary tree {1,#,2,3}, 1 \ 2 / 3 return [1,3,2]. No

一、问题描述 Given a binary tree, return the level order traversal of its nodes' values. (ie, from left to right, level by level). For example: Given binary tree {3,9,20,#,#,15,7}, 3 / \

一、问题描述 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

一、问题描述 Given a binary tree, return the zigzag level order traversal of its nodes' values. (ie, from left to right, then right to left for the next level and alternate between). For example: G

一、问题描述 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

一、问题描述 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. 二、问题分析 利用迭代思想。 三、算法代码

一、问题描述 Rotate an array of n elements to the right by k steps. For example, with n = 7 and k = 3, the array [1,2,3,4,5,6,7] is rotated to [5,6,7,1,2,3,4]. Note: Try to come up as many sol

一、问题描述 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 witho

一、问题描述 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 i

一、问题描述 Given an array of non-negative integers, you are initially positioned at the first index of the array. Each element in the array represents your maximum jump length at that position.

从后往前合并。 public class Solution { public void merge(int[] nums1, int m, int[] nums2, int n) { int a_index = m - 1; int b_index = n - 1; int a_cur = m + n - 1; while(

一、问题描述 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. 二、问题分析 利用递归思想。 三、算法代码

//利用寻找发帖水王解决方法 public class Solution { public int majorityElement(int[] nums) { int cadinate = 0; int ntimes = 0; for(int i = 0; i < nums.length; i++){ if(ntime

public class Solution { public int searchInsert(int[] nums, int target) { int start = 0; int end = nums.length - 1; int middle = 0; while(start <= end){ mi

利用二分查找算法查找target，再结合计数器查找区间（注意：假设i > j，则i和j之间的元素个数count = i - j + 1）。 public class Solution { public int[] searchRange(int[] nums, int target) { int [] result = new int[]{-1, -1};

重要的是把线性下转换成矩阵元素下标 public class Solution { public boolean searchMatrix(int[][] matrix, int target) { int m = matrix.length; int n = matrix[0].length; int start = 0; int end = m * n -

原链表已经从小到大排好序，合并后产生的链表也要保持从小到大的顺序。 public class Solution { public ListNode mergeTwoLists(ListNode l1, ListNode l2) { ListNode head = new ListNode(-1); ListNode cur = head;

一、问题描述 Given an unsorted integer array, find the first missing positive integer. For example, Given [1,2,0] return 3, and [3,4,-1,1] return 2. Your algorithm should run in O(n) time and u

一、问题描述 Merge k sorted linked lists and return it as one sorted list. Analyze and describe its complexity. 二、解题要点 利用分治法，并结合算法Merge Two Sorted Lists 三、算法代码 public class Solution { public

一、问题描述 Given an array with n objects colored red, white or blue, sort them so that objects of the same color are adjacent, with the colors in the order red, white and blue. Here, we will use t

一、问题描述 Given a string containing just the characters '(', ')', '{', '}', '[' and ']', determine if the input string is valid. The brackets must close in the correct order, "()" and "()[]{}" 

一、问题描述 Given a string containing just the characters '(' and ')', find the length of the longest valid (well-formed) parentheses substring. For "(()", the longest valid parentheses substring

一、问题描述 Reverse digits of an integer. Example1: x = 123, return 321 Example2: x = -123, return -321 二、问题分析 1、保存反转结果时，使用long型变量； 2、在计算出反转结果后，需要判断是否溢出 三、算法代码 public class Solution { pub

一、问题描述 Determine whether an integer is a palindrome. Do this without extra space. 二、问题分析 1、分别获取该数的最高位和最低位数字，比较是否一致。 2、当为负数时，返回false。 三、算法代码 public class Solution { public boolean isPalindr

一、问题描述 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. Example:

一、问题描述 Implement pow(x, n). 二、问题分析 在实现分治递归时，结束条件加n==1，可显著提高算法运行效率。 三、算法代码 public class Solution { public double myPow(double x, int n) { if(n < 0){ return 1.0 / pow(x, -

一、问题描述 Implement int sqrt(int x). Compute and return the square root of x. 二、问题分析 返回整型的最接近的平方根。 三、算法代码 public class Solution { public int mySqrt(int x) { if(x < 2){

一、问题描述 Given a binary tree and a sum, determine if the tree has a root-to-leaf path such that adding up all the values along the path equals the given sum. For example: Given the below binary t

一、问题描述 Given a binary tree containing digits from 0-9 only, each root-to-leaf path could represent a number. An example is the root-to-leaf path 1->2->3 which represents the number 123. Fin