Author: devangini123

🌙 Problem Statement: Given an integer array nums, find a subarray that has the largest product, and return the product. The test cases are generated so that the answer will fit in a 32-bit integer. Example 1: Input: nums = [2,3,-2,4] Output: 6 Explanation: [2,3] has the largest product 6. Example 2: Input: nums = [-2,0,-1] Output: 0 Explanation: The result cannot be 2, because [-2,-1] is not a subarray. Constraints 1

🌙 Use Kadane’s Algorithms Problem Statement: Given an integer array nums, find the subarray with the largest sum, and return its sum. Example 1: Input: nums = [-2,1,-3,4,-1,2,1,-5,4] Output: 6 Explanation: The subarray [4,-1,2,1] has the largest sum 6. Example 2: Input: nums = [1] Output: 1 Explanation: The subarray [1] has the largest sum 1. Example 3: Input: nums = [5,4,-1,7,8] Output: 23 Explanation: The subarray [5,4,-1,7,8] has the largest sum 23. Constraints 1

🌙 Problem Statement: You have intercepted a secret message encoded as a string of numbers. The message is decoded via the following mapping: “1” -> ‘A’ “2” -> ‘B’ … “25” -> ‘Y’ “26” -> ‘Z’ However, while decoding the message, you realize that there are many different ways you can decode the message because some codes are contained in other codes (“2” and “5” vs code”25″). For example, “11106” can be decoded into: “AAJF” with the grouping (1, 1, 10, 6) “KJF” with the grouping (11, 10, 6) The grouping (1, 11, 06) is invalid because “06” is not…

🌙 Problem Statement: Given a string s, return the longest palindromic substring in s. Example 1: Input: s = “babad” Output: “bab” Explanation: “aba” is also a valid answer. Example 2: Input: s = “cbbd” Output: “bb” Constraints 1

🌙 Problem Statement: You are given an integer array coins representing coins of different denominations and an integer amount representing a total amount of money. Return the fewest number of coins that you need to make up that amount. If that amount of money cannot be made up by any combination of the coins, return -1. You may assume that you have an infinite number of each kind of coin. Example 1: Input: coins = [1, 2, 5], amount = 11 Output: 3 Explanation: 11 = 5 + 5 + 1 Example 2: Input: coins = [2], amount = 3…

🌙 Problem Statement: Given a string s, return the number of palindromic substrings in it. A string is a palindrome when it reads the same backward as forward. A substring is a contiguous sequence of characters within the string. Example 1: Input: s = “abc” Output: 3 Explanation: Three palindromic strings: “a”, “b”, “c”. Example 2: Input: s = “aaa” Output: 6 Explanation: Six palindromic strings: “a”, “a”, “a”, “aa”, “aa”, “aaa”. Constraints 1 Array(n).fill(null)); let ans = 0; for (let i = 0; i < n; i++) { dp[i][i] = true; ++ans; if (i < n - 1 &&…

🌙 Two ways to implement Dynamic Programming: 1. Bottom-Up (Tabulation): This approach uses iteration to solve the problem. 2. Top-Down (Memoization): This approach uses recursion along with memoization.> Top-Down Approach The image with fib(6) demonstrates the Top-Down approach using recursion and memoization. Where should we store the values? We can store them in an array, map, object, or other data structures. Fetching data from a map or object is generally very fast. Now, let’s solve the Fibonacci number problem using the Top-Down approach. Problem Statement The Fibonacci numbers, commonly denoted F(n) form a sequence, called the Fibonacci sequence, such that…

🌙 Problem Statement: You are a professional robber planning to rob houses along a street. Each house has a certain amount of money stashed. All houses at this place are arranged in a circle. That means the first house is the neighbor of the last one. Meanwhile, adjacent houses have a security system connected, and it will automatically contact the police if two adjacent houses were broken into on the same night. Given an integer array nums representing the amount of money of each house, return the maximum amount of money you can rob tonight without alerting the police. Example…

🌙 Problem Statement: You are given an integer array cost where cost[i] is the cost of ith step on a staircase. Once you pay the cost, you can either climb one or two steps. You can either start from the step with index 0, or the step with index 1. Return the minimum cost to reach the top of the floor. Example 1: Input: cost = [10,15,20] Output: 15 Explanation: You will start at index 1. – Pay 15 and climb two steps to reach the top. The total cost is 15. Example 2: Input: cost = [1,100,1,1,1,100,1,1,100,1] Output: 6…

🌙 Problem Statement: You are climbing a staircase. It takes n steps to reach the top. Each time you can either climb 1 or 2 steps. In how many distinct ways can you climb to the top? Example 1: Input: n = 2 Output: 2 Explanation: There are two ways to climb to the top. 1 step + 1 step 2 steps Example 2: Input: n = 3 Output: 3 Explanation: There are three ways to climb to the top. 1 step + 1 step + 1 step 1 step + 2 steps 2 steps + 1 step Constraints 1