hdu 1542 Atlantis

http://acm.hdu.edu.cn/showproblem.php?pid=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 }

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