坐标离散化

 1 #include <queue>
 2 #include <vector>
 3 #include <cstring>
 4 #include <iostream>
 5 #include <algorithm>
 6 using namespace std;
 7 
 8 int W,H,N;
 9 const int maxn=555;
10 int X1[maxn],X2[maxn],Y1[maxn],Y2[maxn];//开始列,结束列.开始行,结束行 
11 bool fld[6*maxn][6*maxn];
12 int dx[4]={0,0,1,-1};
13 int dy[4]={1,-1,0,0};
14 
15 //坐标离散化 
16 int compress(int *x1,int *x2,int w){
17     vector <int> xs;
18     for(int i=0;i<N;i++){
19         for(int d=-1;d<=1;d++){
20             int tx1=x1[i]+d,tx2=x2[i]+d;
21             if(tx1>=1&&tx1<=w) xs.push_back(tx1);
22             if(tx2>=1&&tx2<=w) xs.push_back(tx2);        
23         }
24     }
25     sort(xs.begin(),xs.end());
26     xs.erase(unique(xs.begin(),xs.end()),xs.end());//去重
27     for(int i=0;i<N;i++){//转变成新的x1,x2 
28         x1[i]=find(xs.begin(),xs.end(),x1[i])-xs.begin();
29         x2[i]=find(xs.begin(),xs.end(),x2[i])-xs.begin();
30     } 
31     return xs.size();
32 }
33 
34 void solve(){
35     //离散化
36     W=compress(X1,X2,W);
37     H=compress(Y1,Y2,H);
38     memset(fld,0,sizeof(fld));
39     
40     //填充网络,交点 
41     for(int i=0;i<N;i++){
42         for(int y=Y1[i];y<=Y2[i];y++){
43             for(int x=X1[i];x<=X2[i];x++){
44                 fld[y][x]=true;
45             }
46         }
47     } 
48     
49     int ans=0;
50     for(int y=0;y<H;y++){
51         for(int x=0;x<W;x++){
52             if(fld[y][x]) continue;
53             ans++;
54             queue < pair<int,int> > Q;
55             Q.push(make_pair(x,y));
56             while(!Q.empty()){
57                 int sx=Q.front().first,sy=Q.front().second;
58                 Q.pop();
59                 for(int i=0;i<4;i++){
60                     int tx=sx + dx[i],ty=sy + dy[i];
61                     if(tx<0 || tx>=W || ty<0 || ty>=H || fld[ty][tx]) continue;
62                     Q.push(make_pair(tx,ty));
63                     fld[ty][tx]=true;
64                 }
65             }
66         }    
67     }
68     cout<<ans<<endl;
69 }
70 
71 int main(){
72     while(cin>>W>>H>>N){
73         for(int i=0;i<N;i++) cin>>X1[i];
74         for(int i=0;i<N;i++) cin>>X2[i];
75         for(int i=0;i<N;i++) cin>>Y1[i];
76         for(int i=0;i<N;i++) cin>>Y2[i];
77         solve();
78     }    
79     return 0;
80 }