hdu 1255

面积并：#include <iostream>#include <string.h>using namespace std;struct node{  int l;  int r;  int cover;  double once;  double len;};node tree[7000];struct Line{   double x;   double y_down;   double y_up;   int cover;};Line line[7000];double yy[7000];bool cmp(Line a,Line b){    if( a.x == b.x )        return a.cover > b.cover;    else       return a.x < b.x;}void Build(int i,int l,int r){    tree[i].l = l;     tree[i].r = r;    tree[i].cover = 0;    tree[i].once = 0.0;    if(tree[i].l == tree[i].r - 1 )        return ;    int mid =(l+r)/2;    Build(i*2,l,mid);    Build(i*2+1,mid,r);}void fun(int i){    if( tree[i].cover >= 2 )    {        tree[i].once = 0;        tree[i].len = yy[tree[i].r] - yy[tree[i].l];        return ;    }    if( tree[i].cover == 1 )    {        if( tree[i].l == tree[i].r - 1 )            tree[i].len = 0;        else            tree[i].len = tree[2*i+1].len + tree[2*i].len + tree[2*i+1].once + tree[2*i].once;        tree[i].once = yy[tree[i].r] - yy[tree[i].l] - tree[i].len;        return ;        }    if( tree[i].cover == 0 )    {        if( tree[i].l == tree[i].r - 1 )            tree[i].len =tree[i].once = 0;        else        {            tree[i].len = tree[2*i+1].len + tree[2*i].len;            tree[i].once =tree[2*i+1].once+tree[2*i].once;        }        return ;    }}void Updata(int i, Line p){    if( yy[tree[i].l] >= p.y_down && yy[tree[i].r] <= p.y_up )    {        tree[i].cover += p.cover;        fun(i);        return ;    }    if( tree[i].l == tree[i].r - 1 ) return ;    int mid = (tree[i].l+tree[i].r)/2;    if( p.y_down <= yy[mid] )        Updata(2*i,p);    if( p.y_up > yy[mid] )        Updata(2*i+1,p);    fun(i);}int main(){    int t,n;    double x1,x2,y1,y2;    scanf("%d",&t);    while( t-- )    {        scanf("%d",&n);        int m = 0;        for(int i=0; i<n; i++)        {            scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2);            line[m].x = x1;             line[m].y_down = y1;             line[m].y_up = y2;            line[m].cover = 1;             yy[m++] = y1;            line[m].x = x2;             line[m].y_down = y1;             line[m].y_up = y2;            line[m].cover = -1;            yy[m++] = y2;        }        sort(yy,yy+m);        sort(line,line+m,cmp);        int i = unique(yy,yy+m) - yy;        Build(1,0,i-1);        double ans = 0;        Updata(1,line[0]);        for(int i=1; i<m; i++)        {           ans += tree[1].len*(line[i].x - line[i-1].x);           Updata(1,line[i]);        }        printf("%.2lf\n",ans);    }return 0;}