堆，支持最大最小

Author: Jiang Haifeng

Heap/src/Heap.java

@@ -0,0 +1,81 @@
+public class Heap<Key extends Comparable<Key>> {
+    private Key[] data;
+    private int capacity;
+    private int count;
+    private boolean isMax;
+
+    public int size() {
+        return count;
+    }
+
+    public boolean isEmpty() {
+        return count == 0;
+    }
+
+    public Heap(int capacity, boolean isMax) {
+        data = (Key[]) new Comparable[capacity + 1];
+        count = 0;
+        this.capacity = capacity;
+        this.isMax = isMax;
+    }
+
+    private boolean less(int i, int j) {
+        return data[i].compareTo(data[j]) < 0;
+    }
+
+    private void exch(int i, int j) {
+        Key tmp = data[i];
+        data[i] = data[j];
+        data[j] = tmp;
+    }
+
+    private boolean needExch(int i, int j) {
+        return (isMax ? less(i, j) : less(j, i));
+    }
+
+    public void swin(int k) {
+        while (k > 1 && needExch(k / 2, k)) {
+            exch(k / 2, k);
+            k = k / 2;
+        }
+    }
+
+    public void sink(int k) {
+        while (k * 2 <= count) {
+            int j = k * 2;
+            if (j < count && needExch(j, j + 1)) j++;
+            if (!needExch(k, j)) break;
+            exch(k, j);
+            k = j;
+        }
+    }
+
+    public void insert(Key key) {
+        data[++count] = key;
+        swin(count);
+    }
+
+    public Key delMax() {
+        Key key = data[1];
+        exch(1, count);
+        data[count--] = null;
+        sink(1);
+        return key;
+    }
+
+    private void sort(Comparable a[]) {
+
+    }
+
+    public static void main(String[] args) {
+        int[] nums = {2, 3, 4, 5, 6};
+        Heap<Integer> maxHeap = new Heap<>(nums.length, false);
+        for (int i = 0; i < nums.length; i++) {
+            maxHeap.insert(nums[i]);
+        }
+        for (int i = 0; i < nums.length; i++) {
+            System.out.println(maxHeap.delMax());
+        }
+    }
+
+}