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36. Valid Sudoku Determine if a 9 x 9 Sudoku board is valid. Only the filled cells need to be validated according to the following rules: Each row must contain the digits 1-9 without repetition. Each column must contain the digits 1-9 without repetition. Each of the nine 3 x 3 sub-boxes of the grid must contain the digits 1-9 without repetition. Note: A Sudoku board (partially filled) could be v..

Question: You are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]). Find two lines that together with the x-axis form a container, such that the container contains the most water. Return the maximum amount of water a container can store. Notice that you may not slant the container. Example 1: Inp..

1.1. Implement an algorithm to determine if a string has all unique characters. What if you cannot use additional data structures? 1) Brute Force (I made this not to use additional data structure) Calculate each item by iterating the string >> result in O(n^2) boolean isUnique(String[] string){ for (int i = 0; i < string.length; i++){ //Since we compute one for i we don't have to start from i ag..

Hash Tables A data structure that maps keys to values for highly efficient lookup. 1. Compute the key's hash code, usually an int or long. Note that two different keys could have the same hash code, as there may be an infinite number of keys and a finite number of ints 2. Then, map the hash code to an index in the array. This could be done with something like hash(key) % array_length. Two differ..

Example: Print all positive integer solutions to the equation a^3 + b^3 = c^3 + d^3 and a, b, c, d are integers between 1 and 1000. 1. A brute force solutions n = 1000 n = 1000 for a from 1 to n for b from 1 to n for c from 1 to n for d from 1 to n if a^3 + b^3 = c^3 + d^3 print a, b, c, d This returns O(n^4) To optimize it we can make a break when we find it n = 1000 for a from 1 to n for b fro..

A problem Solving Flow Chart Listen Pay very close attention to any information in the problem description. You probably need it all for an optimal algorithm. Example Most examples are too small or are special cases. Debug your example. Is there any way it's a special case? Is it big enough? Brute Force get a brute-force solution as soon as possible. Don't worry about developing an efficient alg..

From Cracking the Coding Interview: Question 10: int sumDigits(int n) { int sum = 0; while (n < 0) { num += n % 10; n /= 10; } return sum; } The runtime will be the number of digits in the number. A number with d digits can have a value up to 10^d. if n = 10^d, then d = log n. Therefore, the runtime is 0(log n). Question 11: The following code prints all strings of length k where the characters ..

From Craking the Coding Interview Example 10: boolean isPrime(int n) { for (int x = 2; x * x

Efficient Procedures for solving large scale problems Scalability Classical Data Structures Sorting & Matching Real Implementation of Algorithms in Python Order of this classes Algorithmic Thinking: Peak Finding Sorting & Trees: Event simulation Hashing: Genome comparison Numerics: RSA Encryption (SSL | Backend) Graphs: Rubik's Cube Shortest Paths: Caltech -> MIT Dynamic Programming: Image Compr..