https://www.yaolugnu.com/tags/leetcode/ Recent content in Leetcode on Yao Hugo -- gohugo.io en Sun, 29 May 2022 00:00:00 +0000 https://www.yaolugnu.com/post/string-leetcode/ Sun, 29 May 2022 00:00:00 +0000 https://www.yaolugnu.com/post/string-leetcode/ Leetcode Questions about String 14.longest-common-prefix.java 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 class Solution { public String longestCommonPrefix(String[] strs) { // flower,flow,fly if (strs.length == 0) { return null; } String prefix = strs[0]; int lengths = strs.length; for (int i = 1; i < lengths; i++) { while (strs[i].indexOf(prefix) != 0) { prefix = prefix.substring(0, prefix.length()-1); } } return prefix; } } 125. https://www.yaolugnu.com/post/bubble-sort/ Mon, 20 Sep 2021 00:00:00 +0000 https://www.yaolugnu.com/post/bubble-sort/ Bubble Sort Bubble Sort is a simple sorting algorithm. It compares two adjacent elements and swap them until all elements are in order. It’s not suitable for large data set as its time complexity are of (n2). 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 public class BubbleSort { public static void sort(Comparable[] a){ for(int i = a. https://www.yaolugnu.com/post/quicksort/ Fri, 17 Sep 2021 00:00:00 +0000 https://www.yaolugnu.com/post/quicksort/ Quick Sort Quick sort is a Divide and Conquer algorithm. It partitions a large array into two arrays by a pivot value, and carry out the process recursively so that the entire array becomes an ordered sequence. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 public class QuickSort { public static void main(String[] args) { System. https://www.yaolugnu.com/post/linklist_and_doublylinklist/ Thu, 16 Sep 2021 00:00:00 +0000 https://www.yaolugnu.com/post/linklist_and_doublylinklist/ This demo is to help us identify the different between the Linklist and DoublyLinklist what we need to notice Compare with the Linklist and DoublyLinklist, the Linklist compact with two elements, one is item, another is next point. the DoublyLinklist concact three elements, one is item as well, two others are preview ponit and next point. Linklist Linklist please notice some boundary conditions, like when we insert the elements the index need to be security check (index < 0 || index > N is not allowed) https://www.yaolugnu.com/post/java_in_sparsearray/ Wed, 23 Dec 2020 00:00:00 +0000 https://www.yaolugnu.com/post/java_in_sparsearray/ SharseArray this demo is to help us transform the data from big data to the small data what we need to notic “= new int [11][11];” it means we have a Array is 11*11. 2D to sparseArray, then sparseArray to 2D 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 public class SparseArray { //create init 2D array // 0 means not 1 black 2 blue public static void main(String[] args) { System.