Question: A k-palindrome is a string which transforms into a palindrome on removing at most k characters. Given a string S, and an interger K, print “YES” if S is a k-palindrome; otherwise print “...

一个序列有N个数：A[1],A[2],…,A[N]，求出最长非降子序列的长度。 (讲DP基本都会讲到的一个问题LIS：Longest Increasing Subsequence) 面对这样一个问题，我们首先要定义一个“状态”来代表它的子问题， 并且找到它的解。注意，大部分情况下，某个状态只与它前面出现的状态有关， 而独立于后面的状态。 我们来找一下“状态”和“状态转移方程”。 假如我们考...

From: http://blog.rfaisal.com/2013/05/19/a-crack-at-dynamic-programming/ Dynamic Programming is a discrete optimization technique. It means, the variables we want to calculate using this method are...

找出1～10^n中数字翻转过来是本身的数（ 96 －>96, 18 -> 81, 0 -> 0, 其他数字翻过来都不是数字） 设计一个函数，判断某个只包含数字的字符串是不是Ambigram（比如，69，88，609，818等都是Ambigram）。Follow up：给一个整数n，找出所有长为n的Ambigram。 可以先求出n-2的答案，再利用n-2的答案求出n的答案，...

Question: There is a building of 100 floors  If an egg drops from the Nth floor or above it will break. If it’s dropped from any floor below, it will not break. You’re given 2 eggs. Find N, while m...

Note: This is an extension of House Robber. After robbing those houses on that street, the thief has found himself a new place for his thievery so that he will not get too much attention. This time,...

Write an algorithm that counts the number of ways you can paint a fence with N posts using K colors such that no more than 2 adjacent fence posts are painted with the same color. 因为题目要求是不超过两个相邻...

Given a sequence, find the length of the longest palindromic subsequence in it. For example, if the given sequence is “BBABCBCAB”, then the output should be 7 as “BABCBAB” is the longest palindromic ...

Given integer n, find the number of different binary strings of size n where there are no consecutive 1's.Eg: If n is 2, valid strings are 00, 01, 10. You should return 3.   假设f(n, k)是第n位上为k的数字的个数无...

[问题描述]：　　设有n堆石子排成一排，其编号为1、2、3、…、n（n<=100）。每堆石子的数量用：a[1]、a[2]、…、a[n] 表示，现将这n堆石子归并成一堆，归并的规则： ◆每次只能将相邻两堆归并成一堆，即：第 1 堆石子 a[1] 只能与第 2 堆石子 a[2] 归并，最后一堆石子 a[n] 只能与 a[n-1] 归并，中间的石子 a[i] 只能与 a[i-1] 或 a[i...

Implement regular expression matching with support for '.' and '*'. '.' Matches any single character. '*' Matches zero or more of the preceding element. The matching should cover the entire inp...

Given a string, find the minimum number of characters to be inserted to convert it to palindrome.       For Eg :-            ab:      Number of insertions required is 1. bab            aa:      N...

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 at most two transactions. Note:You may not ...

A message containing letters from A-Z is being encoded to numbers using the following mapping: 'A' -> 1 'B' -> 2 ... 'Z' -> 26 Given an encoded message containing digits, determine t...

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 non...

Given s1, s2, s3, find whether s3 is formed by the interleaving of s1 and s2. For example,Given:s1 = "aabcc",s2 = "dbbca", When s3 = "aadbbcbcac", return true.When s3 = "aadbbbaccc", return false....

The demons had captured the princess (P) and imprisoned her in the bottom-right corner of a dungeon. The dungeon consists of M x N rooms laid out in a 2D grid. Our valiant knight (K) was initially p...

An atm can only dispense values of $1, $5, $20, and $50. Return the number of unique ways that a $ amount of X can be tendered.($1, $5) is distinct from ($5, $1)Input: 4 Output: 1Input: 6 Output: 3I...