芝士猴人，猴人闭嘴，如果你零分并且一分不得

#include<bits/stdc++.h>
using namespace std;
#define int long long
int n,id,ans;
int cntx,cnty;
set<int> sx;
set<int> sy;
int itnx[200005],itny[200005];
map<int,int> ntix,ntiy;
struct square{
	int ux,ly,dx,ry;
}a[100005];
vector<square> b[200005],e[200005];
int tree[800005];
int lazy[800005];
void push_up(int num,int l,int r)
{
	if(l==r)
		tree[num]=(int)(lazy[num]!=0);
	else if(lazy[num]==0)
		tree[num]=tree[num*2]+tree[num*2+1];
	else
		tree[num]=itnx[r]-itnx[l]+1;
}
void ad(int num,int l,int r,int b,int e,int add)
{
	if(b<=l&&r<=e)
	{
		lazy[num]+=add;
		push_up(num,l,r);
		return;
	}
	int mid=(l+r)/2;
	if(b<=mid)
		ad(num*2,l,mid,b,e,add);
	if(mid<e)
		ad(num*2+1,mid+1,r,b,e,add);
	push_up(num,l,r);
}
signed main()
{
	ios::sync_with_stdio(0);
	cout.tie(0);cin.tie(0);
	cin>>n;
	for(int i=1;i<=n;i++)
	{
		cin>>a[i].ux>>a[i].ly>>a[i].dx>>a[i].ry;
		//转格子，us和ly不变，ry本来在前缀和中要加一，和变格子的减一抵消，而dx没有抵消的 
		a[i].dx--;
		sx.insert(a[i].ux),sx.insert(a[i].dx);
		sy.insert(a[i].ly),sy.insert(a[i].ry);
	}
	for(int i:sx)
		itnx[++cntx]=i,ntix[i]=cntx;
	for(int i:sy)
		itny[++cnty]=i,ntiy[i]=cnty;
	for(int i=1;i<=n;i++)
		a[i].ux=ntix[a[i].ux],a[i].dx=ntix[a[i].dx];
	for(int i=1;i<=n;i++)
		a[i].ly=ntiy[a[i].ly],a[i].ry=ntiy[a[i].ry];
	for(int i=1;i<=n;i++)
		b[a[i].ly].push_back(a[i]),e[a[i].ry].push_back(a[i]);
//	cout<<"begin:"<<tree[1]<<"\n";
	for(int i=1;i<cnty;i++)
	{
		for(int j=0;j<b[i].size();j++)
			ad(1,1,cntx,b[i][j].ux,b[i][j].dx,1);
		for(int j=0;j<e[i].size();j++)
			ad(1,1,cntx,e[i][j].ux,e[i][j].dx,-1);
		ans+=(itny[i+1]-itny[i])*tree[1];
//		cout<<i<<","<<itny[i]<<":"<<(itny[i+1]-itny[i])<<"*"<<tree[1]<<"\n";
	}
	cout<<ans;
	return 0;
}
/*
31

2
1 1 5 5
4 4 8 8
begin:0
1,1:3*4
2,4:1*5
3,5:3*2
23

....################
....################
....################
.......#############
###....#############
###....#############
###....#############
####################
####################
####################
*/