Merge pull request #46 from vegetableDogBai/master

week9数据结构作业完成

group23/563253496/week9_datastructure/src/QuickMinStack.java

@@ -0,0 +1,40 @@
+//package com.coding.basic.stack;
+
+import java.util.Collections;
+import java.util.LinkedList;
+import java.util.List;
+
+/**
+ * 设计一个栈，支持栈的push和pop操作，以及第三种操作findMin, 它返回改数据结构中的最小元素
+ * finMin操作最坏的情形下时间复杂度应该是O(1) ， 简单来讲，操作一次就可以得到最小值
+ *
+ * @author liuxin
+ */
+public class QuickMinStack {
+    LinkedList<Integer> list = new LinkedList<Integer>();
+    LinkedList<Integer> temp = new LinkedList<>();
+    int min = Integer.MAX_VALUE;
+
+    public void push(int data) {
+        if (data < min) {
+            min = data;
+        }
+        list.add(data);
+    }
+
+    public int pop() {
+        int num = list.remove(list.size() - 1);
+        if (num == min) {
+            for (int tmp : list) {
+                temp.add(tmp);
+            }
+        }
+        Collections.sort(temp);
+        min = temp.get(0);
+        return list.remove(list.size() - 1);
+    }
+
+    public int findMin() {
+        return min;
+    }
+}

group23/563253496/week9_datastructure/src/StackWithTwoQueues.java

@@ -0,0 +1,53 @@
+/**
+ * Created by bdl19 on 2017/5/6.
+ */
+
+import java.util.*;
+
+
+public class StackWithTwoQueues {
+
+    private Queue<Integer> queue1 = new LinkedList<Integer>();
+    private Queue<Integer> queue2 = new LinkedList<Integer>();
+
+    public void push(int data) {
+        if(queue2.isEmpty()){
+            queue1.add(data);
+        }else{
+            queue2.add(data);
+        }
+    }
+
+    public int pop() {
+        if (queue1.size() == 0 && queue2.size() == 0) {
+            throw new IndexOutOfBoundsException();
+        }
+
+
+
+        if(queue2.isEmpty()){
+            while(!(queue1.size()==1)){
+                queue2.add(queue1.remove());
+            }
+            return queue1.remove();
+
+        }else{
+            while(!(queue2.size()==1)){
+                queue1.add(queue2.remove());
+            }
+            return queue2.remove();
+        }
+
+
+    }
+
+    public static void main(String[] args) {
+        StackWithTwoQueues s = new StackWithTwoQueues();
+        s.push(1);
+        s.push(2);
+        s.push(3);
+        for (int i = 0; i < 3; i++) {
+            System.out.println(s.pop());
+        }
+    }
+}

group23/563253496/week9_datastructure/src/TwoStackInOneArray.java

@@ -0,0 +1,100 @@
+/**
+ * Created by bdl19 on 2017/5/6.
+ */
+public class TwoStackInOneArray {
+    Object[] data = new Object[10];
+
+    private int index1 = 0;
+    private int index2 = data.length - 1;
+
+    private boolean isFull() {
+        if (index1 == index2) {
+            return true;
+        } else return false;
+    }
+
+    private void extendCapacity() {
+        Object[] temp = new Object[data.length + data.length / 2];
+        for (int i = 0; i <= index1; i++) {
+            temp[i] = data[i];
+        }
+        int indext = data.length - 1;
+        for (int i = temp.length - 1; i >= data.length - index2; i--) {
+            temp[i] = indext;
+            indext--;
+        }
+        index2 = temp.length - (temp.length - index1);
+        this.data = temp;
+    }
+
+    /**
+     * 向第一个栈中压入元素
+     *
+     * @param o
+     */
+    public void push1(Object o) {
+        if (this.isFull()) {
+            extendCapacity();
+        }
+        data[index1] = o;
+        index1++;
+
+    }
+
+    /**
+     * 从第一个栈中弹出元素
+     *
+     * @return
+     */
+    public Object pop1() {
+        index1--;
+        Object o = data[index1];
+        data[index1] = null;
+        return o;
+    }
+
+    /**
+     * 获取第一个栈的栈顶元素
+     *
+     * @return
+     */
+
+    public Object peek1() {
+        return data[index1 - 1];
+    }
+
+    /*
+     * 向第二个栈压入元素
+     */
+    public void push2(Object o) {
+        if (this.isFull()) {
+            extendCapacity();
+        }
+        data[index2] = o;
+        index2--;
+    }
+
+    /**
+     * 从第二个栈弹出元素
+     *
+     * @return
+     */
+    public Object pop2() {
+
+        Object o = data[++index2];
+        data[index2] = null;
+        return o;
+    }
+
+    /**
+     * 获取第二个栈的栈顶元素
+     *
+     * @return
+     */
+
+    public Object peek2() {
+
+        return data[index2 + 1];
+    }
+
+}