自己写的一个关于线段树的代码

#include <iostream>using namespace std;#define max(a,b) a>b?a:bstruct LineTree{int left,right;int cover;LineTree *lchild,*rchild;};LineTree* CreateTree(int a,int b) //建立线段树{LineTree *root;root=new LineTree;root->left=a;root->right=b;root->cover=0;if(b-a>1){int mid;mid=(a+b)/2;root->lchild=CreateTree(a,mid);root->rchild=CreateTree(mid,b);}return root;}void Insert(LineTree *t,int a,int b) //插入{int mid;if(t->left>=a && t->right<=b) t->cover++;else{mid=(t->left+t->right)/2;if(b<=mid) Insert(t->lchild,a,b);else if(mid<=a) Insert(t->rchild,a,b);else{Insert(t->lchild,a,mid);Insert(t->rchild,mid,b);}}}void Del(LineTree *t,int a,int b) //删除{int mid;if(t->left>=a && t->right<=b) t->cover--;else{mid=(t->left+t->right)/2;if(b<=mid) Del(t->lchild,a,b);else if(mid<=a) Del(t->rchild,a,b);else{Del(t->lchild,a,mid);Del(t->rchild,mid,b);}}}int sum;void point_count(LineTree *t,int a) //计算a点的个数{if(t->left<=a && t->right>=a)sum+=t->cover;if(t->right-t->left>1){point_count(t->lchild,a);point_count(t->rchild,a);}}int main(){int x,y;LineTree *s;cin>>x>>y;s=CreateTree(x,y);cin>>x>>y;Insert(s,x,y);cin>>x>>y;Insert(s,x,y);cin>>x>>y;Insert(s,x,y);int p1,p2,p3;cin>>p1>>p2>>p3;sum=0;point_count(s,p1);printf("%d/n",sum);sum=0;point_count(s,p2);printf("%d/n",sum);sum=0;point_count(s,p3);printf("%d/n",sum);return 0;}