【坐标离散化】AOJ0531- Paint Color

1 #include<iostream>
2 #include<cstdio>
3 #include<cstring>
4 #include<cstdlib>
5 #include<algorithm>
6 #include<vector>
7 #include<queue>
8 using namespace std;
9 int w,h,n,ans;
10 const int MAXN=1000+10;
11 int x1[MAXN],x2[MAXN],y1[MAXN],y2[MAXN];
12 int hashx[MAXN*2],hashy[MAXN*2];
13 int fld[MAXN*2][MAXN*2];
14 int dx[4]={0,0,1,-1};
15 int dy[4]={1,-1,0,0};
16
17 void compress()
18 {
19     int tx=0,ty=0;
20     for (int i=1;i<=n;i++)
21     {
22         hashx[++tx]=x1[i];hashx[++tx]=x2[i];
23         hashy[++ty]=y1[i];hashy[++ty]=y2[i];
24     }
25     hashx[++tx]=0;hashx[++tx]=w;
26     hashy[++ty]=0;hashy[++ty]=h;
27     sort(hashx+1,hashx+tx+1);
28     sort(hashy+1,hashy+ty+1);
29     w=unique(hashx+1,hashx+tx+1)-(hashx+1);
30     h=unique(hashy+1,hashy+ty+1)-(hashy+1);
31     for (int i=1;i<=n;i++)
32     {
33         x1[i]=lower_bound(hashx+1,hashx+w+1,x1[i])-hashx-1;
34         x2[i]=lower_bound(hashx+1,hashx+w+1,x2[i])-hashx-1;
35         y1[i]=lower_bound(hashy+1,hashy+h+1,y1[i])-hashy-1;
36         y2[i]=lower_bound(hashy+1,hashy+h+1,y2[i])-hashy-1;
37     }
38     w--;h--;
39 }
40
41 void init()
42 {
43     scanf("%d",&n);
44     for (int i=1;i<=n;i++)
45         scanf("%d%d%d%d",&x1[i],&y1[i],&x2[i],&y2[i]);
46     compress();
47 }
48
49 void imos()    /*imos?*/
50 {
51     memset(fld,0,sizeof(fld));
52     for (int i=1;i<=n;i++)
53     {
54         fld[x1[i]][y1[i]]++;
55         fld[x2[i]][y2[i]]++;
56         fld[x1[i]][y2[i]]--;
57         fld[x2[i]][y1[i]]--;
58     }
59
60     for (int i=0;i<w;i++)
61         for (int j=1;j<h;j++)
62             fld[i][j]+=fld[i][j-1];
63
64     for (int j=0;j<h;j++)
65         for (int i=1;i<w;i++)
66             fld[i][j]+=fld[i-1][j];
67 }
68
69 void bfs(int x,int y)
70 {
71     ans++;
72     queue<int> qx,qy;
73     qx.push(x);
74     qy.push(y);
75     fld[x][y]=1;
76     while (!qx.empty())
77     {
78         int xx=qx.front();qx.pop();
79         int yy=qy.front();qy.pop();
80         for (int i=0;i<4;i++)
81         {
82              int nx=xx+dx[i],ny=yy+dy[i];
83              if (nx<0 || ny<0 || nx>w || ny>h || fld[nx][ny]>0) continue;
84              qx.push(nx);
85              qy.push(ny);
86              fld[nx][ny]=1;
87         }
88     }
89 }
90
91 void solve()
92 {
93     ans=0;
94     for (int i=0;i<w;i++)
95         for (int j=0;j<h;j++)
96             if (fld[i][j]==0) bfs(i,j);
97     printf("%d\n",ans);
98 }
99
100 int main()
101 {
102     //freopen("input.txt","r",stdin);
103     //freopen("output.txt","w",stdout);
104     while (~scanf("%d%d",&w,&h)&&w&&h)
105     {
106         init();
107         imos();
108         solve();
109     }
110     return 0;
111 }