liujunlovecs的专栏

Using HashSet. public class Solution { public int lengthOfLongestSubstring(String s) { if (s == null || s.length() == 0) { return 0; } Set set = new H

public class Solution { public int[] twoSum(int[] nums, int target) { if (nums == null || nums.length < 2) { return null; } Map map = new HashMap();

public class Solution { public List> fourSum(int[] nums, int target) { List> result = new ArrayList>(); if (nums == null || nums.length < 3) { return result;

public class Solution { public List findSubstring(String s, String[] words) { List result = new ArrayList(); if (s == null || s.length() == 0 || words.length == 0) {

public class Solution { public boolean isValidSudoku(char[][] board) { if (board == null || board.length == 0 || board[0].length == 0) { return false; }

public class Solution { public List> groupAnagrams(String[] strs) { List> result = new ArrayList>(); if (strs == null || strs.length == 0) { return result;

public class Solution { public String minWindow(String s, String t) { String result = ""; if (s == null || t == null || s.length() < t.length()) { return resul

public class Solution { public int maximalRectangle(char[][] matrix) { if (matrix == null || matrix.length == 0 || matrix[0].length == 0) { return 0; } int row