排序算法

src/main/java/org/sheep/Main.java

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+package org.sheep;
+
+//TIP To <b>Run</b> code, press <shortcut actionId="Run"/> or
+// click the <icon src="AllIcons.Actions.Execute"/> icon in the gutter.
+public class Main {
+    public static void main(String[] args) {
+        //TIP Press <shortcut actionId="ShowIntentionActions"/> with your caret at the highlighted text
+        // to see how IntelliJ IDEA suggests fixing it.
+        System.out.printf("Hello and welcome!");
+
+        for (int i = 1; i <= 5; i++) {
+            //TIP Press <shortcut actionId="Debug"/> to start debugging your code. We have set one <icon src="AllIcons.Debugger.Db_set_breakpoint"/> breakpoint
+            // for you, but you can always add more by pressing <shortcut actionId="ToggleLineBreakpoint"/>.
+            System.out.println("i = " + i);
+        }
+    }
+}

src/main/java/org/sheep/MinStack.java

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+package org.sheep;
+
+import java.util.Stack;
+
+public class MinStack {
+     private Stack<Integer> stack;
+     private Stack<Integer> minStack;
+
+     public MinStack() {
+         stack = new Stack<>();
+         minStack = new Stack<>();
+     }
+
+     public void push(int x) {
+         stack.push(x);
+         if (minStack.empty() || x < minStack.peek()) {
+             minStack.push(x);
+         } else {
+             minStack.push(minStack.peek());
+         }
+     }
+
+     public void pop() {
+         stack.pop();
+         minStack.pop();
+     }
+
+     public int top() {
+         return stack.peek();
+     }
+
+     public int getMin() {
+         return minStack.peek();
+     }
+}

src/main/java/org/sheep/alg/ConversionOfNumber.java

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+package org.sheep.alg;
+
+/**
+ * 进制转换
+ * @author sheep
+ */
+public class ConversionOfNumber {
+    public static void main(String[] args) {
+        // 定义二进制数
+        int a = -0b1001;
+        System.out.println(a);
+        // 定义16进制数
+        int b = 0x10;
+        System.out.println(b);
+        // 取反
+        System.out.println(~a + 1);
+        // | & ^
+        int c = 0b0001010;
+        int d = 0b0000110;
+        printBinary(c | d);
+        printBinary(c & d);
+        printBinary(c ^ d);
+        int e = -3;
+        System.out.println(Integer.toBinaryString(e >> 2));
+        System.out.println(Integer.toBinaryString(e >>> 2));
+    }
+
+    /**
+     * 十进制转换二进制
+     * @param num
+     */
+    public static void printBinary(int num) {
+        for (int i = 31; i >= 0; i--) {
+            System.out.print((num & (1 << i)) == 0 ? "0" : "1" );
+        }
+        System.out.println();
+    }
+}

src/main/java/org/sheep/alg/Sort.java

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+package org.sheep.alg;
+
+import java.util.Arrays;
+
+/**
+ * 排序
+ * @author sheep
+ */
+public class Sort {
+    int[] arr = {5,3,4,1,2};
+
+    public static void main(String[] args) {
+        Sort sort = new Sort();
+        sort.insertSort(sort.arr);
+        System.out.println(Arrays.toString(sort.arr));
+    }
+
+    /**
+     * 交换数组中指定位置的两个数
+     * @param arr
+     * @param i
+     * @param j
+     */
+    private void swap(int[] arr, int i, int j) {
+        int temp = arr[i];
+        arr[i] = arr[j];
+        arr[j] = temp;
+    }
+
+    /**
+     * 选择排序
+     */
+    public void selectSort(int[] arr) {
+        if (arr == null || arr.length < 2) { return; }
+        for (int i = 0; i < arr.length; i++) {
+            for (int j = i + 1; j < arr.length; j++) {
+                if (arr[i] > arr[j]) {
+                    swap(arr, i, j);
+                }
+            }
+        }
+    }
+
+    /**
+     * 冒泡排序
+     */
+    public void bubbleSort(int[] arr) {
+        if (arr == null || arr.length < 2) { return; }
+        for (int i = 0; i < arr.length; i++) {
+            for (int j = 0; j < arr.length - i - 1; j++) {
+                if (arr[j] > arr[j + 1]) {
+                    swap(arr, j, j + 1);
+                }
+            }
+        }
+    }
+
+    /**
+     * 插入排序
+     */
+    public void insertSort(int[] arr) {
+        if (arr == null || arr.length < 2) { return; }
+        for (int i = 1; i < arr.length; i++) {
+            for (int j = i; j > 0; j--) {
+                if (arr[j] < arr[j - 1]) {
+                    swap(arr, j, j - 1);
+                }
+            }
+        }
+    }
+}

src/main/java/org/sheep/alg/Test.java

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+package org.sheep.alg;
+
+import java.util.Arrays;
+
+/**
+ * 测试
+ * @author sheep
+ */
+public class Test {
+
+    private static void swap(int[] arr, int i, int j) {
+        int temp = arr[i];
+        arr[i] = arr[j];
+        arr[j] = temp;
+    }
+
+    public static void main(String[] args) {
+        int[] arr = {5,3,4,1,2};
+//        for (int i = 0; i < arr.length; i++) {
+//            for (int j = 0; j < arr.length - i -1; j++) {
+//                if (arr[j] > arr[j + 1]) {
+//                    swap(arr, j, j + 1);
+//                }
+//            }
+//        }
+
+//        for (int i = 0; i < arr.length; i++) {
+//            for (int j = i + 1; j < arr.length; j++) {
+//                if (arr[j] < arr[i]) {
+//                    swap(arr, i, j);
+//                }
+//            }
+//        }
+
+//        for (int i = 1; i < arr.length; i++) {
+//            for (int j = i; j > 0; j--) {
+//                if (arr[j] < arr[j - 1]) {
+//                    swap(arr, j, j - 1);
+//                }
+//            }
+//        }
+        System.out.println(Arrays.toString(arr));
+    }
+}