单旋版本的伸展树

Splay(Single-Rotation).cpp

@@ -0,0 +1,93 @@
+#include <cstdio>
+
+#define NIL 0
+
+using namespace std;
+
+struct node
+{
+	int key, value;
+	node *ch[2];
+	node(int _key = 0, int _value = 0) : key(_key), value(_value) { ch[0] = ch[1] = NIL; }
+}*root;
+
+void rotate(node *&u, int dir)
+{
+	node *o = u->ch[dir];
+	u->ch[dir] = o->ch[dir ^ 1];
+	o->ch[dir ^ 1] = u;
+	u = o;
+}
+
+void insert(node *&u, int key, int value)
+{
+	if (u == NIL)
+	{
+		u = new node(key, value);
+		return;
+	}
+	if (key < u->key)
+	{
+		insert(u->ch[0], key, value);
+		rotate(u, 0);
+	}
+	else if (key > u->key)
+	{
+		insert(u->ch[1], key, value);
+		rotate(u, 1);
+	}
+}
+
+int find(node *&u, int key)
+{
+	if (u == NIL)
+	{
+		return -1;
+	}
+	if (u->key == key)
+	{
+		return u->value;
+	}
+	int res;
+	if (key < u->key)
+	{
+		res = find(u->ch[0], key);
+		if (u->ch[0] != NIL)
+			rotate(u, 0);
+	}
+	else if (key > u->key)
+	{
+		res = find(u->ch[1], key);
+		if (u->ch[1] != NIL)
+			rotate(u, 1);
+	}
+	return res;
+}
+
+int main()
+{
+	int in, key, value;
+	while (true)
+	{
+		scanf("%d", &in);
+		if (in == 1)
+		{
+			scanf("%d%d", &key, &value);
+			insert(root, key, value);
+		}
+		else if (in == 2)
+		{
+			scanf("%d", &key);
+			printf("%d\n", find(root, key));
+		}
+		else if (in == 0)
+		{
+			return 0;
+		}
+		else
+		{
+			printf("No such command!\n");
+		}
+	}
+	return 0;
+}