UVALive 6663 Count the Regions --离散化+DFS染色

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
#include <vector>
#include <map>
using namespace std;
#define N 207

vector<int> vx,vy;
map<int,int> hx,hy;
int dx[4] = {0,0,1,-1};
int dy[4] = {1,-1,0,0};
int vis[N][N];
int l[55],r[55],t[55],b[55];

bool OK(int nx,int ny)
{
    if(nx >= 0 && nx <= 201 && ny >= 0 && ny <= 201 && !vis[nx][ny])
        return 1;
    return 0;
}

void dfs(int x,int y)
{
    vis[x][y] = 1;
    for(int k=0;k<4;k++)
    {
        int nx = x + dx[k];
        int ny = y + dy[k];
        if(OK(nx,ny))
            dfs(nx,ny);
    }
}

int main()
{
    int n,i,j;
    while(scanf("%d",&n)!=EOF && n)
    {
        vx.clear();vy.clear();
        hx.clear();hy.clear();
        for(i=0;i<n;i++)
        {
            scanf("%d%d%d%d",&l[i],&t[i],&r[i],&b[i]);
            vx.push_back(l[i]);
            vx.push_back(r[i]);
            vy.push_back(t[i]);
            vy.push_back(b[i]);
        }
        sort(vx.begin(),vx.end());
        vx.erase(unique(vx.begin(),vx.end()),vx.end());  //运用STL巧妙去重
        sort(vy.begin(),vy.end());
        vy.erase(unique(vy.begin(),vy.end()),vy.end());
        for(i=0;i<vx.size();i++)  //以2为间隔，防止出现面积为1的小矩形计算不到的情况
            hx[vx[i]] = 2*i+1;
        for(i=0;i<vy.size();i++)
            hy[vy[i]] = 2*i+1;
        for(i=0;i<n;i++)  //离散后的值
        {
            l[i] = hx[l[i]];
            t[i] = hy[t[i]];
            r[i] = hx[r[i]];
            b[i] = hy[b[i]];
        }
        memset(vis,0,sizeof(vis));
        for(i=0;i<n;i++)    //边界赋值
        {
            for(j=b[i];j<=t[i];j++)
            {
                vis[j][l[i]] = 1;
                vis[j][r[i]] = 1;
            }
            for(j=l[i];j<=r[i];j++)
            {
                vis[t[i]][j] = 1;
                vis[b[i]][j] = 1;
            }
        }
        int cnt = 0;
        for(i=0;i<=201;i++)
        {
            for(j=0;j<=201;j++)
            {
                if(!vis[i][j])
                {
                    cnt++;
                    dfs(i,j);
                }
            }
        }
        printf("%d\n",cnt);
    }
    return 0;
}