2 seconds

256 megabytes

standard input

standard output

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
const int N=1e5+4;
int n,x1,x2,y3,y2,rec[2*N],num;
struct no
{int l,r,h,flag;
};
no line[8*N];
struct nod
{int l,r,cover;ll sum;
};
nod tree[8*N];
int cmp(no x,no y)
{return x.h<y.h;
}
void build(int node,int L,int R)
{tree[node].l=L,tree[node].r=R;tree[node].cover=tree[node].sum=0;if(L>=R)return ;int mid=(L+R)>>1;build(2*node,L,mid);build(2*node+1,mid+1,R);
}
void Pushup(int node)
{if(tree[node].cover){tree[node].sum=rec[tree[node].r+1]-rec[tree[node].l];}else{if(tree[node].l==tree[node].r)tree[node].sum=0;else tree[node].sum=tree[2*node].sum+tree[2*node+1].sum;}
}
void update(int node,int L,int R,int x)
{if(L<=tree[node].l&&R>=tree[node].r){tree[node].cover+=x;Pushup(node);return ;}int mid=(tree[node].l+tree[node].r)>>1;if(L>mid) update(2*node+1,L,R,x);else if(R<=mid)update(2*node,L,R,x);else{update(2*node,L,mid,x);update(2*node+1,mid+1,R,x);}Pushup(node);
}
int bi(int x)
{int L=1,R=num-1,mid;while(L<=R){mid=(L+R)>>1;if(rec[mid]==x)return mid;else if(rec[mid]>x)R=mid-1;else L=mid+1;}return -1;
}
int main()
{scanf("%d",&n);int cnt=1;for(int i=1;i<=n;i++){scanf("%d%d%d%d",&x1,&y3,&x2,&y2);if(x1>x2)swap(x1,x2);if(y3>y2)swap(y3,y2);rec[cnt] = line[cnt].l = x1;line[cnt].r = x2+1;line[cnt].h = y3;line[cnt++].flag = 1;line[cnt].l = x1;rec[cnt] = line[cnt].r = x2+1;line[cnt].h = y2+1;line[cnt++].flag = -1;}sort(line+1,line+cnt,cmp);sort(rec+1,rec+cnt);num = 2;for(int i = 2;i < cnt;i++){if(rec[i]!=rec[i-1])rec[num++]=rec[i];}build(1,1,num-1);ll ans=0;for(int i = 1;i < cnt-1;i++){int fx = bi(line[i].l);int fy = bi(line[i].r)-1;if(fx <= fy){update(1,fx,fy,line[i].flag);}ans+=tree[1].sum*(ll)(line[i+1].h-line[i].h);}cout<<ans<<"\n";return 0;
}