Try it on GfG Practice Given two string s1 and s2 of same length, the task is to check whether s2 is a rotation of s1. Examples: Input: s1 = "abcd", s2 = "cdab" Output: true Explanation: After 2 right rotations, s1 will become equal to s2. Input: s1 = "aab", s2 = "aba" Output: true Explanation:…

Try it on GfG Practice Given two arrays a[] and b[], the task is to find all starting indices of b[] as a subarray in a[]. Examples: Input: a[] = [2, 3, 0, 3, 0, 3, 0], b[] = [3, 0, 3, 0] Output: [1, 3] Explanation: The subarray a[1...4] = b[] and subarray a[3...6] = b[]. Input : a[] = [1, 2, 3, 4,…

Given a string S and a character C, the task is to count the number of substrings of S that contains only the character C. Examples: Input: S = "0110111", C = '1' Output: 9 Explanation: The substrings containing only '1' are: "1" — 5 times "11" — 3 times "111" — 1 time Hence, the count is 9. Input:…

Given a string s containing lowercase alphabets, the task is to print the sub-strings that contain all the vowels at-least one time and there are no consonants (non-vowel characters) present in the sub-strings. Examples: Input: s = "aeoibsddaaeiouudb" Output: ["aaeiouu", "aeiouu", "aeiou", "aaeiou"]…

Given a text txt and a pattern pat of size n and m respectively, the task is to find all occurrences of pat and its permutations (or anagrams) in txt. You may assume n > m. Examples: Input: txt = "BACDGABCDA", pat = "ABCD" Output: [0, 5, 6] Explanation: "BACD" is at 0, "ABCD" at 5 and "BCDA" at 6…

Suffix Tree is very useful in numerous string processing and computational biology problems. Many books and e-resources talk about it theoretically and in few places, code implementation is discussed. But still, I felt something is missing and it’s not easy to implement code to construct suffix tree…

In earlier suffix tree articles, we created suffix tree for one string and then we queried that tree for substring check, searching all patterns, longest repeated substring and built suffix array (All linear time operations).There are lots of other problems where multiple strings are involved. e.g.…

In Manacher’s Algorithm Part 1 and Part 2, we gone through some of the basics, understood LPS length array and how to calculate it efficiently based on four cases. In Part 3, we implemented the same. Here we will review the four cases again and try to see it differently and implement the same. All…

Given an input string and a pattern, the task is to find the frequency of occurrences of the string pattern in a given string. Examples: Input: pattern = "man", string = "dhimanman" Output: 2 Input: pattern = "nn", string = "Banana" Output: 0 Input: pattern = "aa", string = "aaaaa" Output : 4…

Given a stream of characters (characters are received one by one), write a function that prints 'Yes' if a character makes the complete string palindrome, else prints 'No'. Examples: Input: str[] = "abcba" Output: a Yes // "a" is palindrome b No // "ab" is not palindrome c No // "abc" is not…

Given an input text and an array of k words, arr[], find all occurrences of all words in the input text. Let n be the length of text and m be the total number of characters in all words, i.e. m = length(arr[0]) + length(arr[1]) + … + length(arr[k-1]). Here k is total numbers of input words. Example:…

Pattern searching is an important problem in computer science. When we do search for a string in a notepad/word file, browser, or database, pattern searching algorithms are used to show the search results. A typical problem statement would be- ” Given a text txt[0..n-1] and a pattern pat[0..m-1]…

Background Suffix Array : A suffix array is a sorted array of all suffixes of a given string. Let the given string be "banana". 0 banana 5 a 1 anana Sort the Suffixes 3 ana 2 nana ----------------> 1 anana 3 ana alphabetically 0 banana 4 na 4 na 5 a 2 nana The suffix array for "banana" : suffix[] =…

We strongly recommend to read following post on suffix trees as a pre-requisite for this post. Pattern Searching | Set 8 (Suffix Tree Introduction) A suffix array is a sorted array of all suffixes of a given string. The definition is similar to Suffix Tree which is compressed trie of all suffixes of…

Given a text txt[0..n-1] and a pattern pat[0..m-1], write a function search(char pat[], char txt[]) that prints all occurrences of pat[] in txt[]. You may assume that n > m. Examples: Input: txt[] = "THIS IS A TEST TEXT" pat[] = "TEST" Output: Pattern found at index 10 Input: txt[] =…

Try it on GfG Practice Given two strings txt and pat, the task is to return all indices of occurrences of pat within txt. Examples: Input: txt = "abcab", pat = "ab" Output: [0, 3] Explanation: The string "ab" occurs twice in txt, first occurrence starts from index 0 and second from index 3. Input:…

This algorithm efficiently locates all instances of a specific pattern within a text in linear time. If the length of the text is “n” and the length of the pattern is “m,” then the total time taken is O(m + n), with a linear auxiliary space. It is worth noting that the time and auxiliary space of…

Given a text T[0. . .n-1] and a pattern P[0. . .m-1], write a function search(char P[], char T[]) that prints all occurrences of P[] present in T[] using Rabin Karp algorithm. You may assume that n > m. Examples: Input: T[] = “THIS IS A TEST TEXT”, P[] = “TEST” Output: Pattern found at index 10…

Given text string with length n and a pattern with length m, the task is to prints all occurrences of pattern in text. Note: You may assume that n > m. Examples: Input: text = “THIS IS A TEST TEXT”, pattern = “TEST” Output: Pattern found at index 10 Input: text = “AABAACAADAABAABA”, pattern = “AABA”…

Pattern searching is an algorithm that involves searching for patterns such as strings, words, images, etc. We use certain algorithms to do the search process. The complexity of pattern searching varies from algorithm to algorithm. They are very useful when performing a search in a database. The…

Try it on GfG Practice Given two arrays, val[] and wt[], representing the values and weights of items, and an integer capacity representing the maximum weight a knapsack can hold, the task is to determine the maximum total value that can be achieved by putting items in the knapsack. You are allowed…

Given an array job[], where each element represents the time required to complete a specific job. There are k identical assignees available to complete these jobs, and each assignee takes t units of time to complete one unit of a job. The task is to determine the minimum time required to complete…

Try it on GfG Practice The three stacks s1, s2 and s3, each containing positive integers, are given. The task is to find the maximum possible equal sum that can be achieved by removing elements from the top of the stacks. Elements can be removed from the top of each stack, but the final sum of the…

Try it on GfG Practice Given two arrays, arr[] and dep[], that represent the arrival and departure times of trains respectively, the task is to find the minimum number of platforms required so that no train waits. Examples: Input: arr[] = [900, 940, 950, 1100, 1500, 1800], dep[] = [910, 1200, 1120,…

Try it on GfG Practice Given an array arr[] of rope lengths, connect all ropes into a single rope with the minimum total cost. The cost to connect two ropes is the sum of their lengths. Examples: Input: arr[] = [4, 3, 2, 6] Output: 29 Explanation: We can connect the ropes in following ways. 1) First…

We introduced graph coloring and applications in previous post. As discussed in the previous post, graph coloring is widely used. Unfortunately, there is no efficient algorithm available for coloring a graph with minimum number of colors as the problem is a known NP Complete problem. There are…

Try it on GfG Practice Given n number of friends who have to give or take some amount of money from one another. The task is to design an algorithm by which the total cash flow among all the friends is minimized to settle all debts. Examples: Input: transaction = [[0, 1000, 2000], [0, 0, 5000], [0,…

Try it on GfG Practice Given an amount of n Rupees and an infinite supply of each of the denominations {1, 2, 5, 10} valued coins/notes, The task is to find the minimum number of coins needed to make the given amount. Examples: Input: n= 39 Output: 6 Explanation: We need a 50 Rs note and a 20 Rs…

Try it on GfG Practice Given two arrays: deadline[] and profit[], where the index of deadline[] represents a job ID, and deadline[i] denotes the deadline for that job and profit[i] represents profit of doing ith job. Each job takes exactly one unit of time to complete, and only one job can be…

The Dijkstra's Algorithm, we can either use the matrix representation or the adjacency list representation to represent the graph, while the time complexity of Dijkstra's Algorithm using matrix representation is O(V^2). The time complexity of Dijkstra's Algorithm using adjacency list representation…

Try it on GfG Practice Huffman coding is a lossless data compression algorithm. The idea is to assign variable-length codes to input characters, lengths of the assigned codes are based on the frequencies of corresponding characters. The variable-length codes assigned to input characters are Prefix…

We recommend reading the following two posts as a prerequisite to this post. Greedy Algorithms | Set 5 (Prim’s Minimum Spanning Tree (MST)) Graph and its representations We have discussed Prim's algorithm and its implementation for adjacency matrix representation of graphs. The time complexity for…

We recommend to read following post as a prerequisite for this. Greedy Algorithms | Set 3 (Huffman Coding) Time complexity of the algorithm discussed in above post is O(nLogn). If we know that the given array is sorted (by non-decreasing order of frequency), we can generate Huffman codes in O(n)…

Try it on GfG Practice Given n activities with start times in start[] and finish times in finish[], find the maximum number of activities a single person can perform without overlap. A person can only do one activity at a time. Examples: Input: start[] = [1, 3, 0, 5, 8, 5], finish[] = [2, 4, 6, 7,…

C++/WinRT pull request 1225 fixed a problem with a call to invoke. What’s the problem, why did it show up all of a sudden, and what can you do if you are stuck on an older version of C++/WinRT? namespace winrt::impl { ⟦ ... ⟧ template bool invoke(Delegate const& delegate, Arg const&... args)…

Consider the following API: enum class WidgetFlavor { Vanilla, Chocolate, Strawberry, Other, }; WidgetFlavor GetWidgetFlavor(HWIDGET widget); The idea here is that Widgets come in three flavors today, but we might add new flavors in the future, so we add an Other value to cover any future flavors.…

Some time ago, we investigated how C++/WinRT decides which interfaces your class implements when you use the implements template. I promised to talk about unwrap_implements_t at some point in the future, so I guess now’s the time. template > struct unwrap_implements { using type = T; }; template …

Coffee cools, buildings crumble, eggs break and stars fizzle out in a universe that seems destined to degrade into a state of uniform drabness known as thermal equilibrium. The astronomer-philosopher Sir Arthur Eddington in 1927 cited the gradual dispersal of energy as evidence of an irreversible…