HDU 1542 Atlanta

Http://acm.hdu.edu.cn/showproblem.php? PID = 1, 1542

  1 #include <cstdio>  2 #include <cstring>  3 #include <algorithm>  4 #define maxn 200000  5 using namespace std;  6   7 int n;  8 double Y[maxn],X[maxn];  9 struct point 10 { 11     double x; 12     double y1; 13     double y2; 14     int lr; 15     bool operator <(const point &a)const 16     { 17         return x<a.x; 18     } 19 } p[maxn]; 20  21 struct node 22 { 23     int l,r; 24     double x; 25     double y1; 26     double y2; 27     int cover; 28     double len; 29 } tree[maxn*4]; 30  31 void build(int i,int l,int r) 32 { 33     tree[i].l=l; 34     tree[i].r=r; 35     tree[i].x=-1; 36     tree[i].y1=Y[l]; 37     tree[i].y2=Y[r]; 38     tree[i].cover=0; 39     tree[i].len=0; 40     if(l==r-1) return ; 41     int mid=(l+r)>>1; 42     build(i<<1,l,mid); 43     build(i<<1|1,mid,r); 44 } 45  46 void update(int i,double l,double r,int lr) 47 { 48     if(Y[tree[i].l]==l&&Y[tree[i].r]==r) 49     { 50         tree[i].cover+=lr; 51         if(tree[i].cover) 52         { 53             tree[i].len=Y[tree[i].r]-Y[tree[i].l]; 54         } 55         else if(tree[i].l==tree[i].r-1) tree[i].len=0; 56         else 57             tree[i].len=tree[i<<1].len+tree[i<<1|1].len; 58         return; 59     } 60     int mid=(tree[i].l+tree[i].r)>>1; 61     if(r<=Y[mid]) 62     { 63         update(i<<1,l,r,lr); 64     } 65     else if(l>=Y[mid]) 66     { 67         update(i<<1|1,l,r,lr); 68     } 69     else 70     { 71         update(i<<1,l,Y[mid],lr); 72         update(i<<1|1,Y[mid],r,lr); 73     } 74     if(tree[i].cover) 75     { 76         tree[i].len=Y[tree[i].r]-Y[tree[i].l]; 77     } 78     else if(tree[i].l==tree[i].r-1) tree[i].len=0; 79     else 80         tree[i].len=tree[i<<1].len+tree[i<<1|1].len; 81 } 82  83 int main() 84 { 85     int cas=1; 86     while(scanf("%d",&n)!=EOF) 87     { 88         if(n==0) break; 89         int t1=0; 90         for(int i=0; i<n; i++) 91         { 92             double x1,y1,x2,y2; 93             scanf("%lf%lf%lf%lf",&x1,&y1,&x2,&y2); 94             p[t1].x=x1; 95             p[t1].y1=y1; 96             p[t1].y2=y2; 97             p[t1].lr=1; 98             Y[t1++]=y1; 99             p[t1].x=x2;100             p[t1].y1=y1;101             p[t1].y2=y2;102             p[t1].lr=-1;103             Y[t1++]=y2;104         }105         sort(Y,Y+t1);106         sort(p,p+t1);107         int cnt=unique(Y,Y+t1)-Y;108         build(1,0,cnt-1);109         double x=0;110         double s=0;111         for(int i=0; i<t1; i++)112         {113             s+=(p[i].x-x)*tree[1].len;114             update(1,p[i].y1,p[i].y2,p[i].lr);115             x=p[i].x;116         }117         printf("Test case #%d\n",cas);118         cas++;119         printf("Total explored area: %.2lf\n",s);120         printf("\n");121     }122     return 0;123 }

View code