POJ 1151 离散化线段树＋计算几何正矩形求并

我觉得像我这样把所有东西都写的类的ACMer真是一个异类。。。

 

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  1 //Result:wizmann    1151    Accepted    832K    0MS    G++    3310B    

  2 #include <cstdio>

  3 #include <cstdlib>

  4 #include <cstring>

  5 #include <algorithm>

  6 #include <string>

  7 #include <cmath>

  8 #include <vector>

  9 #include <set>

 10 #include <map>

 11 #include <iostream>

 12 

 13 using namespace std;

 14 

 15 #define print(x) cout<<x<<endl

 16 #define input(x) cin>>x

 17 #define SIZE 128

 18 

 19 struct node

 20 {

 21     int st,end;

 22     double len;

 23     int cov;

 24 

 25     node(){}

 26     node(int ist,int iend,double ilen)

 27     {

 28         cov=0;

 29         st=ist;end=iend;

 30         len=ilen;

 31     }

 32     

 33     bool equal(int a,int b)

 34     {

 35         return st==a && end==b;

 36     }

 37     

 38     int getmid()

 39     {

 40         return (st+end)>>1;

 41     }

 42     

 43     bool endnode()

 44     {

 45         return end-st<=1;

 46     }

 47 };

 48 

 49 struct point

 50 {

 51     double x,y;

 52     point(){}

 53     point(double i_x,double i_y)

 54     {

 55         x=i_x;y=i_y;

 56     }

 57 };

 58 

 59 struct segment

 60 {

 61     point p1,p2;

 62 

 63     segment(){}

 64     segment(const point& a,const point& b)

 65     {

 66         p1=a;p2=b;

 67     }

 68 };

 69 

 70 struct line

 71 {

 72     double y;

 73     int x1,x2;

 74     int flag;

 75     line(){}

 76     line(int ix1,int ix2,double iy,int iflag)

 77     {

 78         x1=ix1;x2=ix2;

 79         y=iy;flag=iflag;

 80     }

 81     friend bool operator < (const line& a,const line& b)

 82     {

 83         return a.y<b.y;

 84     }

 85 };

 86 

 87 const int ROOT=0;

 88 

 89 

 90 node stree[SIZE<<2];

 91 int n;

 92 map<double,int> hash;

 93 map<int,double> anti_hash;

 94 int sz,ind;

 95 line edge[SIZE<<1];

 96 

 97 

 98 inline int left(int x)

 99 {

100     return (x<<1)+1;

101 }

102 inline int right(int x)

103 {

104     return left(x)+1;

105 }

106 

107 void stree_init(int l,int r,int pos=ROOT)

108 {

109     stree[pos]=node(l,r,anti_hash[r+1]-anti_hash[l]);

110     if(l<r)

111     {

112         int mid=(l+r)>>1;

113         stree_init(l,mid,left(pos));

114         stree_init(mid+1,r,right(pos));

115     }

116 }

117 

118 void update(int l,int r,int cov,int pos=ROOT)

119 {

120     if(stree[pos].equal(l,r))

121     {

122         stree[pos].cov+=cov;

123     }

124     else

125     {

126         int mid=stree[pos].getmid();

127         if(r<=mid) update(l,r,cov,left(pos));

128         else if(l>mid) update(l,r,cov,right(pos));

129         else

130         {

131             update(l,mid,cov,left(pos));

132             update(mid+1,r,cov,right(pos));

133         }

134     }

135 }

136 

137 double query(int pos=ROOT)

138 {

139     double res=0;

140     if(stree[pos].cov>0) res+=stree[pos].len;

141     else if(stree[pos].st!=stree[pos].end)

142     {

143         res+=query(left(pos));

144         res+=query(right(pos));

145     }

146     return res;

147 }

148 

149 int main()

150 {

151     double bx,by,ex,ey;

152     int cas=1;

153     while(input(n) && n)

154     {

155         hash.clear();

156         anti_hash.clear();

157         vector<double> itemx;

158         vector<segment> seg;

159         for(int i=0;i<n;i++)

160         {

161             scanf("%lf%lf%lf%lf",&bx,&by,&ex,&ey);

162             itemx.push_back(bx);

163             itemx.push_back(ex);

164             seg.push_back(segment(point(bx,by),point(ex,by)));

165             seg.push_back(segment(point(bx,ey),point(ex,ey)));

166         }

167         sort(itemx.begin(),itemx.end());

168         sz=itemx.size();

169         ind=0;

170         double ans=0;

171         for(int i=0;i<sz;i++)

172         {

173             if(hash.find(itemx[i])==hash.end())

174             {

175                 //print(itemx[i]<<' '<<ind);

176                 hash[itemx[i]]=ind;

177                 anti_hash[ind]=itemx[i];

178                 ind++;

179             }

180         }

181         sz=seg.size();

182         for(int i=0;i<(int)seg.size();i+=2)

183         {

184             edge[i]=line(hash[seg[i].p1.x],hash[seg[i].p2.x]-1,seg[i].p1.y,1);

185             edge[i+1]=line(hash[seg[i+1].p1.x],hash[seg[i+1].p2.x]-1,seg[i+1].p1.y,-1);

186         }

187         sort(edge,edge+sz);

188         stree_init(0,ind-1);

189         update(edge[0].x1,edge[0].x2,edge[0].flag);

190         for(int i=1;i<sz;i++)

191         {

192             ans+=fabs(edge[i-1].y-edge[i].y)*query();

193             update(edge[i].x1,edge[i].x2,edge[i].flag);

194         }

195         printf("Test case #%d\n",cas++);

196         printf("Total explored area: %.2f\n\n",ans); 

197     }

198     return 0;

199 }