手写一个节点大小平衡树（SBT）模板，留着用

#include<stdio.h>
#include<string.h>
struct s
{
int key,left,right,size;
}tree[10010];
int top;
void left_rot(int &x)// 左旋
{
int y=tree[x].right;
tree[x].right=tree[y].left;
tree[y].left=x;
tree[y].size=tree[x].size;
tree[x].size=tree[tree[x].left].size+tree[tree[x].right].size+1;
x=y;
}
void right_rot(int &x)//右旋
{
int y=tree[x].left;
tree[x].left=tree[y].right;
tree[y].right=x;
tree[y].size=tree[x].size;
tree[x].size=tree[tree[x].left].size+tree[tree[x].right].size+1;
x=y;
}
void maintain(int &x,bool flag)//维护SBT状态
{
if(flag==false)//左边
{
if(tree[tree[tree[x].left].left].size>tree[tree[x].right].size)//左孩子的左孩子大于右孩子
right_rot(x);
else
if(tree[tree[tree[x].left].right].size>tree[tree[x].right].size)//左孩子的右孩子大于右孩子
{
left_rot(tree[x].left);
right_rot(x);
}
else
return;
}
else//右边
{
if(tree[tree[tree[x].right].right].size>tree[tree[x].left].size)//右孩子的右孩子大于左孩子
left_rot(x);
else
if(tree[tree[tree[x].right].left].size>tree[tree[x].left].size)//右孩子的左孩子大于左孩子
{
right_rot(tree[x].right);
left_rot(x);
}
else
return;
}
maintain(tree[x].left,false);
maintain(tree[x].right,true);
maintain(x,true);
maintain(x,false);
}
void insert(int &x,int key)//插入
{
if(x==0)
{
x=++top;
tree[x].left=0;
tree[x].right=0;
tree[x].size=1;
tree[x].key=key;
}
else
{
tree[x].size++;
if(key<tree[x].key)
insert(tree[x].left,key);
else
insert(tree[x].right,key);//相同元素可插右子树
maintain(x,key>=tree[x].key);
}
}
int remove(int &x,int key)//利用后继删除
{
tree[x].size--;
if(key>tree[x].key)
remove(tree[x].right,key);
else
if(key<tree[x].key)
remove(tree[x].left,key);
else
if(tree[x].left!=0&&tree[x].right==0)//有左子树，无右子树
{
int temp=x;
x=tree[x].left;
return temp;
}
else
if(!tree[x].left&&tree[x].right!=0)//有右子树，无左子树
{
int temp=x;
x=tree[x].right;
return temp;
}
else
if(!tree[x].left&&!tree[x].right)//无左右子树
{
int temp=x;
x=0;
return temp;
}
else//左右子树都有
{
int temp=tree[x].right;
while(tree[temp].left)
temp=tree[temp].left;
tree[x].key=tree[temp].key;
remove(tree[x].right,tree[temp].key);
}
}
int getmin(int x)//求最小值
{
while(tree[x].left)
x=tree[x].left;
return tree[x].key;
}
int getmax(int x)//求最大值
{
while(tree[x].right)
x=tree[x].right;
return tree[x].key;
}
int pred(int &x,int y,int key)//前驱，y初始前驱，从0开始, 最终要的是返回值的key值
{
if(x==0)
return y;
if(key>tree[x].key)
return pred(tree[x].right,x,key);
else
return pred(tree[x].left,y,key);
}
int succ(int &x,int y,int key)//后继，同上
{
if(x==0)
return y;
if(key<tree[x].key)
return succ(tree[x].left,x,key);
else
return succ(tree[x].right,y,key);
}
int select(int &x,int k)//选第k小的数
{
int r=tree[tree[x].left].size+1;
if(r==k)
return tree[x].key;
else
if(r<k)
return select(tree[x].right,k-r);
else
return select(tree[x].left,k);
}
int rank(int &x,int key)//key排第几
{
if(key<tree[x].key)
{
return rank(tree[x].left,key);
}
else
if(key>tree[x].key)
return rank(tree[x].right,key)+tree[tree[x].left].size+1;
else
return tree[tree[x].left].size+1;
}
void order(int &x)
{
if(x==0)
return;
order(tree[x].left);
printf("%d\n",tree[x].key);
order(tree[x].right);
}
int main()
{
top=0;
}