扫描线

求矩形面积并，周长并。

P5490 【模板】扫描线

#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;
typedef long long ll;
const int N=400005;
ll n,ans;
struct node{
	int x,yy,y;
	int v;
}a[N<<1];
struct Node{
	int l,r;
	int len,v;
}t[N*6]; 
ll b[N<<1];
ll cnt;
ll read(){
	ll num=0,f=1;
	char c=getchar();
	while(c<'0'||c>'9'){
		if(c=='-') f=-1;
		c=getchar();
	}
	while(c>='0'&&c<='9'){
		num=num*10+c-'0';
		c=getchar();
	}
	return f*num;
}
bool cmp(node aa,node bb){
	return aa.x<bb.x;
}
void pushup(ll k){
	if(t[k].v) t[k].len=b[t[k].r+1]-b[t[k].l];
	else t[k].len=t[k<<1].len+t[k<<1|1].len;
}
void build(ll k,ll l,ll r){
	t[k].l=l; t[k].r=r;
	if(l==r) return;
	ll mid=(l+r)>>1;
	build(k<<1,l,mid);
	build(k<<1|1,mid+1,r);
}
void update(ll k,ll x,ll y,ll l,ll r,ll v){
	if(l<=x&&y<=r){
		t[k].v+=v;
		pushup(k);
		return;
	}
	ll mid=(x+y)>>1;
	if(l<=mid) update(k<<1,x,mid,l,r,v);
	if(r>mid) update(k<<1|1,mid+1,y,l,r,v);
	pushup(k);
}
int main(){
	n=read();
	for(int i=1;i<=n;i++){
		a[i].x=read(); a[i].y=read(); a[i+n].x=read(); a[i].yy=read();
		a[i+n].y=a[i].y; a[i+n].yy=a[i].yy; a[i].v=1; a[i+n].v=-1;
		b[++cnt]=a[i].x;
		b[++cnt]=a[i].y;
		b[++cnt]=a[i+n].x;
		b[++cnt]=a[i].yy;
	}
	sort(b+1,b+cnt+1);
	ll m=unique(b+1,b+cnt+1)-b-1;
	for(int i=1;i<=n;i++){
		a[i].x=lower_bound(b+1,b+m+1,a[i].x)-b;
		a[i+n].x=lower_bound(b+1,b+m+1,a[i+n].x)-b;
		a[i+n].y=a[i].y=lower_bound(b+1,b+m+1,a[i].y)-b;
		a[i+n].yy=a[i].yy=lower_bound(b+1,b+m+1,a[i].yy)-b;
	}
	sort(a+1,a+n*2+1,cmp);
	build(1,1,m);
	for(int i=1;i<=2*n;i++){
		ans+=(b[a[i].x]-b[a[i-1].x])*t[1].len;
		update(1,1,m,a[i].y,a[i].yy-1,a[i].v);
	}
	printf("%lld",ans);
	return 0;
} 

hdu1542

#include<cstdio>
#include<iostream>
#include<algorithm>
using namespace std;
const int N=100005;
typedef long long ll;
int cnt;
int n,T;
double ans;
struct node{
    double x,yy,y;
    int v;
}a[N<<1];
double b[N<<1];
struct Node{
    double len;
    int l,r;
    int v;
}t[N<<3];
bool cmp(node aa,node bb){
    return aa.x<bb.x;
}
void pushup(int k){
    if(t[k].v) t[k].len=b[t[k].r+1]-b[t[k].l];
    else t[k].len=t[k<<1].len+t[k<<1|1].len;
}
void update(int k,int l,int r,int x,int y,int v){
    if(x<=l&&r<=y){
        t[k].v+=v;
        pushup(k); 
        return;
    }
    int mid=(l+r)>>1;
    if(x<=mid) update(k<<1,l,mid,x,y,v);
    if(y>mid) update(k<<1|1,mid+1,r,x,y,v);
    pushup(k);
}
void build(int k,int l,int r){
    t[k].l=l; t[k].r=r;
    if(l==r) return;
    int mid=(l+r)>>1;
    build(k<<1,l,mid);
    build(k<<1|1,mid+1,r);
}
int main(){
    while(~scanf("%d",&n)&&n!=0){
        ans=0;
        for(int i=1;i<=n;i++){
            scanf("%lf%lf%lf%lf",&a[i].x,&a[i].y,&a[i+n].x,&a[i].yy);
            a[i+n].y=a[i].y; a[i+n].yy=a[i].yy;
            a[i].v=1; a[i+n].v=-1;
            b[++cnt]=a[i].x;
            b[++cnt]=a[i].y;
            b[++cnt]=a[i].yy;
            b[++cnt]=a[i+n].x;
        }
        sort(b+1,b+cnt+1);
        int m=unique(b+1,b+cnt+1)-b-1;
        for(int i=1;i<=n;i++){
            a[i].x=lower_bound(b+1,b+m+1,a[i].x)-b;
            a[i+n].x=lower_bound(b+1,b+m+1,a[i+n].x)-b;
            a[i].y=a[i+n].y=lower_bound(b+1,b+m+1,a[i].y)-b;
            a[i].yy=a[i+n].yy=lower_bound(b+1,b+m+1,a[i].yy)-b;
        }
        sort(a+1,a+n*2+1,cmp);
        build(1,1,m);
        for(int i=1;i<=2*n;i++){
            ans+=(b[(int)a[i].x]-b[(int)a[i-1].x])*t[1].len;
            update(1,1,m,a[i].y,a[i].yy-1,a[i].v);
        }
        printf("Test case #%d
",++T);
        printf("Total explored area: %.2f

",ans);
    }
    return 0;
}

hdu 1828

hdu 3265