算法题 - 随笔分类(第12页) - Pickle

LeetCode——Valid Palindrome

摘要：Description：Given a string, determine if it is a palindrome, considering only alphanumeric characters and ignoring cases.For example, "A man, a plan, ... 阅读全文

posted @ 2015-06-19 22:48 Pickle 阅读(176) 评论(0) 推荐(0)

LeetCode——Pascal's Triangle II

摘要：Description：Given an index k, return the kth row of the Pascal's triangle.For example, given k = 3, Return [1,3,3,1].public class Solution { public... 阅读全文

posted @ 2015-06-19 21:53 Pickle 阅读(207) 评论(0) 推荐(0)

LeetCode——Pascal's Triangle

摘要：Description：Given numRows, generate the first numRows of Pascal's triangle.For example, given numRows = 5, Return[ [1], [1,1], [1,2,1], [1,3... 阅读全文

posted @ 2015-06-19 21:42 Pickle 阅读(184) 评论(0) 推荐(0)

LeetCode——Balanced Binary Tree

摘要：Description：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 whi... 阅读全文

posted @ 2015-06-19 11:57 Pickle 阅读(186) 评论(0) 推荐(0)

LeetCode——Min Stack

摘要：Description：Design a stack that supports push, pop, top, and retrieving the minimum element in constant time.push(x) -- Push element x onto stack.pop(... 阅读全文

posted @ 2015-06-19 00:04 Pickle 阅读(208) 评论(0) 推荐(0)

LeetCode——Count and Say

摘要：Description：The count-and-say sequence is the sequence of integers beginning as follows: 1, 11, 21, 1211, 111221, ...1 is read off as "one 1" or 11. 1... 阅读全文

posted @ 2015-06-18 19:38 Pickle 阅读(187) 评论(0) 推荐(0)

LeetCode——Invert Binary Tree

摘要：Description：Invert a binary tree. 4 / \ 2 7/ \ / \1 3 6 9to 4 / \ 7 2 / \ / \9 6 3 1递归invert就好了。/** * Definition for a binary tree ... 阅读全文

posted @ 2015-06-16 23:58 Pickle 阅读(217) 评论(0) 推荐(0)

LeetCode——Contains Duplicate II

摘要：Description： Given an array of integers and an integer k, find out whether there there are two distinct indices i and j in the array such that nums[i... 阅读全文

posted @ 2015-06-16 23:37 Pickle 阅读(273) 评论(0) 推荐(0)

LeetCode——Number of 1 Bits

摘要：//求一个整数的二进制串中1的个数public int hammingWeight(int n) { String b_str = Integer.toBinaryString(n); int b_count = 0; for(int i=0; i<b_str.length(... 阅读全文

posted @ 2015-06-01 23:54 Pickle 阅读(212) 评论(0) 推荐(0)

Leetcode-Compare Version Numbers

摘要：判断产品版本号的大小。public class Solution { public int compareVersion(String version1, String version2) { String[] v1 = version1.split("\\."); ... 阅读全文

posted @ 2015-05-24 19:14 Pickle 阅读(172) 评论(0) 推荐(0)

LeetCode-Rotate Array

摘要：从右向左旋转数组，一共k次。k可以是任意数字。public class Solution { public void rotate(int[] nums, int k) { if(k == 0 || nums.length==0 || nums.length==1) ret... 阅读全文

posted @ 2015-05-21 23:43 Pickle 阅读(176) 评论(0) 推荐(0)

LeetCode - Isomorphic Strings

摘要：题意很好理解，判断两个字符串的结构是否相同。测试数据里有？{}【】等符号啊，果断扩大到300.public class Solution { public static boolean isIsomorphic(String s, String t) { if(isIsomorphicOn... 阅读全文

posted @ 2015-05-21 15:24 Pickle 阅读(170) 评论(0) 推荐(0)

LeetCode——Reverse Linked List

摘要：反转链表，用了一个比较笨的方法。public class Solution { public ListNode reverseList(ListNode head) { if(head == null || head.next == null) retur... 阅读全文

posted @ 2015-05-20 23:28 Pickle 阅读(202) 评论(0) 推荐(0)

LeetCode - Factorial Trailing Zeroes

摘要：找出n！中零的个数。对n!做质因数分解n!=2x*3y*5z*... 显然0的个数等于min(x,z)，并且min(x,z)==z 证明：对于阶乘而言，也就是1*2*3*...*n [n/k]代表1~n中能被k整除的个数那么很显然 [n/2] > [n/5] (左边是逢2增1，右边是逢5增1... 阅读全文

posted @ 2015-05-06 15:59 Pickle 阅读(170) 评论(0) 推荐(0)

LeetCode - Minimum Depth of Binary Tree

摘要：求二叉树的最小深度。/** * Definition for binary tree * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x) ... 阅读全文

posted @ 2015-04-29 00:30 Pickle 阅读(159) 评论(0) 推荐(0)

LeetCode - Path sum

摘要：判断一颗二叉树中是否存在一天路径（从根节点到叶子节点）的val值之和等于给定的sum。注意判断root为null的时候。成也递归败也递归。。。。。/** * Definition for binary tree * public class TreeNode { * int val; *... 阅读全文

posted @ 2015-04-28 23:08 Pickle 阅读(194) 评论(0) 推荐(0)

LeetCode - Count Primes

摘要：判断小于n数中素数的个数，如果用普通的判断方法会超时，这里使用筛选法。具体请参考：http://blog.csdn.net/liukehua123/article/details/5482854public class Solution { public int countPrimes(i... 阅读全文

posted @ 2015-04-27 23:14 Pickle 阅读(187) 评论(0) 推荐(0)

LeetCode - Remove Linked List Elements

摘要：删除链表中的指定元素。/** * Definition for singly-linked list. * public class ListNode { * int val; * ListNode next; * ListNode(int x) { val = x; } ... 阅读全文

posted @ 2015-04-26 22:16 Pickle 阅读(235) 评论(0) 推荐(0)

LeetCode - Binary Tree Level Order Traversal II

摘要：把上一个类似的题目中的list反转就可以了。/** * Definition for binary tree * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * Tree... 阅读全文

posted @ 2015-04-26 21:38 Pickle 阅读(191) 评论(0) 推荐(0)

LeetCode - Maximum Depth of Binary Tree

摘要：递归求二叉树的最大深度。/** * Definition for binary tree * public class TreeNode { * int val; * TreeNode left; * TreeNode right; * TreeNode(int x... 阅读全文

posted @ 2015-04-25 23:18 Pickle 阅读(169) 评论(0) 推荐(0)

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