标签: 位运算 题目: Using O(1) time to check whether an integer n is a power of 2. 解题思路: 这道题是利用位运算判断一个数是不是2 的整数次方思路:1. 如果一个数是2的整数次方的话,那么他的二进制表现形式上只有一位是1,其余的都会是02. 如果将n-1那么在原先所在的那一位就会变为0,其余之后的位数都会变成1,例如:16: 10000 ,15:011113. 将两者进行与运算,num&(num-1), 则所有的位上都会为0,这…

标签: 位运算 描述: Count how many 1 in binary representation of a 32-bit integer. 解题思路: 统计一个int型的数的二进制表现形式中1的个数1.与check power of 2中的解题形式非常相似,同样利用num&(num-1) 的结果来检查num中二进制形式上1的个数,区别在于Check Power of 2 是来检查是否存在1,而这一题主要是检查有几个1.2. 此题可以利用 num = num&(num-1) 每次进…

最近开始刷lintcode,记录下自己的答案,数字即为lintcode题目号,语言为python3,坚持日拱一卒吧... (一). 回文字符窜问题(Palindrome problem) 627. Longest Palindrome 给出一个包含大小写字母的字符串.求出由这些字母构成的最长的回文串的长度是多少. 数据是大小写敏感的,也就是说,"Aa" 并不会被认为是一个回文串 输入 : s = "abccccdd" 输出 : 7 说明 : 一种可以构建出来的最长回…

标签:动态规划 题目描述: Given two strings, find the longest common subsequence (LCS). Your code should return the length of LCS. 解题思路: 这一题是非常经典的动态规划问题,在解题思路上可以按照经典的动态规划的解法,这是在系统学习动态规划之后第一个解决的LintCode上的问题: 1.子问题划分 给出两个字符串的A,B,两个字符串长度分别为lenA,lenB,求出两个字符串的LCS: 这划…

标签: 动态规划 题目描述: There are a row of n houses, each house can be painted with one of the k colors. The cost of painting each house with a certain color is different. You have to paint all the houses such that no two adjacent houses have the same color.…

标签: 动态规划 描述: Find the contiguous subarray within an array (containing at least one number) which has the largest product.   For example, given the array [2,3,-2,4], the contiguous subarray [2,3] has the largest product = 6. 解题思路: 前面几道题有点儿过分依赖答案了,后面还是…

标签:动态规划 题目描述: Given a 2D binary matrix filled with 0's and 1's, find the largest square containing all 1's and return its area. Example For example, given the following matrix: 1 0 1 0 0 1 0 1 1 1 1 1 1 1 1 1 0 0 1 0 Return 4. 解题思路: 1.这一题明显使用动态规划来解题,…

标签:动态规划 描述: Given two words word1 and word2, find the minimum number of steps required to convert word1 to word2. (each operation is counted as 1 step.) You have the following 3 operations permitted on a word: Insert a character Delete a character Re…

标签:动态规划 题目描述: Given a string S and a string T, count the number of distinct subsequences of T in S. A subsequence of a string is a new string which is formed from the original string by deleting some (can be none) of the characters without disturbing…

标签: 动态规划 描述: Given an integer array nums with all positive numbers and no duplicates, find the number of possible combinations that add up to a positive integer target. Example Given nums = [1, 2, 4], target = 4 The possible combination ways are: [1,…