# Java Solution

## Pow(x n) LeetCode Solution

Implement pow(x, n), which calculates x raised to the power n.

## Group Anagrams LeetCode Solution

Given an array of strings strs, group the anagrams together. You can return the answer in any order.

## Rotate Image LeetCode Solution

You are given an n x n 2D matrix representing an image, rotate the image by 90 degrees (clockwise).

## Permutations II LeetCode Solution

Given a collection of numbers, nums, that might contain duplicates, return all possible unique permutations in any order.

## Jump Game II LeetCode Solution

You are given a 0-indexed array of integers nums of length n. You are initially positioned at nums. Each element nums[i] represents the maximum length of a forward jump from index i. In other words, if you are at nums[i], you can jump to any nums[i + j] where: 0 <= j <= nums[i] and i + j < n. Return the minimum number of jumps to reach nums[n - 1].

## Wildcard Matching LeetCode Solution

Given an input string (s) and a pattern (p), implement wildcard pattern matching with support for ‘?’ and ‘*’ where: ‘?’ Matches any single character.’*’ Matches any sequence of characters (including the empty sequence).The matching should cover the entire input string.

## Multiply Strings LeetCode Solution

Given two non-negative integers num1 and num2 represented as strings, return the product of num1 and num2, also represented as a string.

## Trapping Rain Water LeetCode Solution

Given n non-negative integers representing an elevation map where the width of each bar is 1, compute how much water it can trap after raining.

## First Missing Positive LeetCode Solution

Given an unsorted integer array nums, return the smallest missing positive integer.

## Combination Sum II LeetCode Solution

Given a collection of candidate numbers (candidates) and a target number (target), find all unique combinations in candidates where the candidate numbers sum to target.

## Combination Sum LeetCode Solution

Given an array of distinct integers candidates and a target integer target, return a list of all unique combinations of candidates where the chosen numbers sum to target. You may return the combinations in any order.

## Swap Nodes in Pairs LeetCode Solution

Given a linked list, swap every two adjacent nodes and return its head. You must solve the problem without modifying the values in the list’s nodes.

## Longest Valid Parentheses LeetCode Solution

Given a string containing just the characters ‘(‘ and ‘)’, return the length of the longest valid (well-formed) parentheses substring.

## Permutations LeetCode Solution

Given an array nums of distinct integers, return all the possible permutations. You can return the answer in any order.

## Largest Rectangle in Histogram LeetCode Solution

Given an array of integers heights representing the histogram’s bar height where the width of each bar is 1, return the area of the largest rectangle in the histogram.