thatkris

/* * @lc app=leetcode id=78 lang=java * * [78] Subsets * * https://leetcode.com/problems/subsets/description/ * * algorithms * Medium (76.47%) * Likes: 16199 * Dislikes: 243 * Total Accepted: 1.7M * Total Submissions: 2.2M * Testcase Example: '[1,2,3]' * * Given an integer array nums of unique elements, return all possible subsets * (the power set). * * The solution set must not contain duplicate subsets. Return the solution in * any order. * * * Example 1: * * * Input: nums = [1,2,3] * Output: [[],[1],[2],[1,2],[3],[1,3],[2,3],[1,2,3]] * * * Example 2: * * * Input: nums = [0] * Output: [[],[0]] * * * * Constraints: * * * 1 <= nums.length <= 10 * -10 <= nums[i] <= 10 * All the numbers of nums are unique. * * * * solution： * 问题拆分成 从n个元素的数组中选者k个元素的素全组合, 再收集所有组合即可 */ // @lc code=start import java . util . ArrayList ; class Solution { public List < List < Integer >> subsets ( int [] nums) { ...

/* Tags backtracking * @lc app=leetcode id=77 lang=java * * [77] Combinations * * https://leetcode.com/problems/combinations/description/ * * algorithms * Medium (69.56%) * Likes: 7886 * Dislikes: 206 * Total Accepted: 822.7K * Total Submissions: 1.2M * Testcase Example: '4\n2' * * Given two integers n and k, return all possible combinations of k numbers * chosen from the range [1, n]. * * You may return the answer in any order. * * * Example 1: * * * Input: n = 4, k = 2 * Output: [[1,2],[1,3],[1,4],[2,3],[2,4],[3,4]] * Explanation: There are 4 choose 2 = 6 total combinations. * Note that combinations are unordered, i.e., [1,2] and [2,1] are considered * to be the same combination. * * * Example 2: * * * Input: n = 1, k = 1 * Output: [[1]] * Explanation: There is 1 choose 1 = 1 total combination. * * * * Constraints: * * * 1 <= n <= 20 * 1 <= k <= n * * */ // @lc code=start import java . util . ArrayList ; impor...

/* * @lc app=leetcode id=40 lang=java * * [40] Combination Sum II * * https://leetcode.com/problems/combination-sum-ii/description/ * * algorithms * Medium (53.88%) * Likes: 9859 * Dislikes: 261 * Total Accepted: 861.2K * Total Submissions: 1.6M * Testcase Example: '[10,1,2,7,6,1,5]\n8' * * 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. * * Each number in candidates may only be used once in the combination. * * Note: The solution set must not contain duplicate combinations. * * * Example 1: * * * Input: candidates = [10,1,2,7,6,1,5], target = 8 * Output: * [ * [1,1,6], * [1,2,5], * [1,7], * [2,6] * ] * * * Example 2: * * * Input: candidates = [2,5,2,1,2], target = 5 * Output: * [ * [1,2,2], * [5] * ] * * * * Constraints: * * * 1 <= candidates.length <= 100 * 1 <= candida...