C code. C code run. Run code run… please!
This question is available on both Leetcode (No. 270) and Lintcode (No. 901). The question is not too hard, if we do not chase the best time complexity. For example, we can traversal all the nodes and book-keep the closest … Read More »
Question Name: Hills Question Description: An integer array store the heights of some consecutive hills. Find a minimum integer N, so that you could increase/decrease the heights of the hills by any integer in range [0, N]. After the adjustment, … Read More »
Question Name: Deviation Question Description: Given an array of integer elements and an integer d, please consider all the sequences of d consecutive elements in the array. For each sequence we compute the difference between the maximum and the minimum … Read More »
This morning, I suddenly remembered this challenge. But I nearly forgot the answer. I’d better to record it here for latter review. Question Name: Find the Abnormal Number Question Description: in a given integer array, every number, except one, appears … Read More »
Question Name: Simulate Stack With Two Queues
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 | /** * Filename : StackWithTwoQueues.java * Dependency: None * Author : Sheng Yu (codesays.com) * Create at : 2014-08-03 * JDK used : 1.7 * Change log: None */ import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.io.StreamTokenizer; import java.util.NoSuchElementException; import java.util.Queue; import java.util.concurrent.LinkedBlockingQueue; /** * @author Sheng Yu (codesays.com) * @param <T>: the type of dealing data. */ class Stack<T> { // main queue always stores the elements. // swap is used in pop() function to hold the elements temporarily. private Queue<T> main = new LinkedBlockingQueue<T>(); private Queue<T> swap = new LinkedBlockingQueue<T>(); // Used in pop() function to exchange he main and swap queues. private Queue<T> temp = null; /** * @param item: to push into the stack. */ public void push(T item) { main.add(item); } /** * @return T: remove and return the most recent element in the stack. * @throws NoSuchElementException: pop when queue is empty. */ public T pop() throws NoSuchElementException { T result = null; // swap is always empty at the beginning of popping. if (main.size() == 0) { throw new NoSuchElementException("Queue is empty"); } // Move all data in main queue to swap, except the most recent one. while (main.size() > 1) { swap.add(main.remove()); } // Get the most recent element. result = main.remove(); // Exchange main and swap queue, so that we always push new data into // main queue. temp = main; main = swap; swap = temp; return result; } } public class StackWithTwoQueues { /** * Stub for test * @param args * @throws IOException * @throws NoSuchElementException * @throws IllegalArgumentException */ public static void main(String[] args) throws IOException, NoSuchElementException, IllegalArgumentException { StreamTokenizer st = new StreamTokenizer(new BufferedReader( new InputStreamReader(System.in))); Stack<Integer> test = new Stack<Integer>(); boolean popSuc = true; Integer res = 0; String instruction = null; while (st.nextToken() != StreamTokenizer.TT_EOF) { instruction = st.sval; if (instruction.equalsIgnoreCase("POP")) { try{ popSuc = true; res = test.pop(); } catch (NoSuchElementException e) { // Failed to pop something. popSuc = false; System.out.println(-1); } if (popSuc) { // Successful to pop something. System.out.println(res); } } else if (instruction.equalsIgnoreCase("PUSH")){ st.nextToken(); test.push((int)st.nval); } else { throw new IllegalArgumentException(instruction + "is invalid."); } } } } |
Questioin Name: Count Visible Nodes in Binary Tree Question: In a binary tree, if in the path from root to the node A, there is no node with greater value than A’s, this node A is visible. We need to … Read More »
Question Name: Print Tree By Columns Question: print tree by columns, from leftmost column to rightmost column. For each node in i(th) column, if son(s) exist, its left son is in the (i-1)th column, and right son in the (i+1)th … Read More »
Question: To generate a K-subset in a uniformly random manner from N elements. We have two slightly different solutions. The first one is quite straightforward: shuffle the elements, and then return the first K elements. In such solution, the space … Read More »
Question: if you hava an array with n integers. These integers are in random order. And each interger is between 1 and n-1, including 1 and n-1. Additionally, there is one and only one integer, which appears twice, while all … Read More »