更新

2026-08-11 17:41:36 +08:00
parent cfe4c82c90
commit 03fe4ddf9d
18771 changed files with 3617239 additions and 0 deletions
@@ -0,0 +1,79 @@
+var Class = require('./Class');
+var swap = require('./swap');
+var isSorted = require('./isSorted');
+exports = Class({
+    initialize: function Heap() {
+        var cmp =
+            arguments.length > 0 && arguments[0] !== undefined
+                ? arguments[0]
+                : isSorted.defComparator;
+        this._cmp = cmp;
+        this.clear();
+    },
+    clear: function() {
+        this._data = [];
+        this.size = 0;
+    },
+    add: function(item) {
+        this._data.push(item);
+        this.size++;
+        this._heapifyUp(this.size - 1);
+        return this.size;
+    },
+    poll: function() {
+        var data = this._data;
+        if (this.size > 0) {
+            var item = data[0];
+            data[0] = data[this.size - 1];
+            this.size--;
+            this._heapifyDown(0);
+            return item;
+        }
+    },
+    peek: function() {
+        if (this.size > 0) {
+            return this._data[0];
+        }
+    },
+    _heapifyUp: function(idx) {
+        var data = this._data;
+        var parent = parentIdx(idx);
+        while (idx > 0 && this._cmp(data[parent], data[idx]) > 0) {
+            swap(data, parent, idx);
+            idx = parent;
+            parent = parentIdx(idx);
+        }
+    },
+    _heapifyDown: function(idx) {
+        var size = this.size;
+        var cmp = this._cmp;
+        var data = this._data;
+        while (leftChildIdx(idx) < size) {
+            var smallerIdx = leftChildIdx(idx);
+            var rightChild = rightChildIdx(idx);
+            if (
+                rightChild < size &&
+                cmp(data[rightChildIdx], data[smallerIdx]) < 0
+            ) {
+                smallerIdx = rightChild;
+            }
+            if (cmp(data[idx], data[smallerIdx]) < 0) {
+                break;
+            } else {
+                swap(data, idx, smallerIdx);
+            }
+            idx = smallerIdx;
+        }
+    }
+});
+function parentIdx(idx) {
+    return Math.floor((idx - 1) / 2);
+}
+function leftChildIdx(idx) {
+    return 2 * idx + 1;
+}
+function rightChildIdx(idx) {
+    return 2 * idx + 2;
+}
+
+module.exports = exports;