Uva 12171 离散化加BFS

对每一个长方体的坐标离散化处理 假想空气对空气bfs求联通

#include<bits/stdc++.h>
using namespace std;
const int maxn = 50 + 5;
const int maxc = 1000 + 1;
int n;
int x0[maxn], y0[maxn], z0[maxn], x1[maxn], y1[maxn], z1[maxn];
int xs[maxn*2], ys[maxn*2], zs[maxn*2], nx, ny, nz;
int color[maxn*2][maxn*2][maxn*2];
int dx[] = {0, 0, 0, 0, -1, 1};
int dy[] = {0, 0, -1, 1, 0, 0};
int dz[] = {-1, 1, 0, 0, 0, 0};
struct Cell
{
    int x, y, z;
    Cell(int x = 0, int y = 0, int z = 0) : x(x), y(y), z(z) {}
    void setVis() const {
        color[x][y][z] = 2;
    }
    int volume() const {
        return (xs[x+1]-xs[x])*(ys[y+1]-ys[y])*(zs[z+1]-zs[z]);
    }
    Cell neighbor(int i) const {
        return Cell(x+dx[i], y+dy[i], z+dz[i]);
    }
    bool valid() const {
        return x>=0 && x<nx-1 && y>=0 && y<ny-1 && z>=0 && z<nz-1;
    }
    bool solid() const {
        return color[x][y][z] == 1;
    }
    int area(int i) const {
        if (dx[i] != 0) return (ys[y+1]-ys[y])*(zs[z+1]-zs[z]);
        else if(dy[i] != 0) return (xs[x+1]-xs[x])*(zs[z+1]-zs[z]);
        else return (xs[x+1]-xs[x])*(ys[y+1]-ys[y]);
    }
    bool getVis() const {
        return color[x][y][z] == 2;
    }
};
void floodfill(int& s, int& v)  //bfs 统计
{
    s = v = 0;
    Cell c; c.setVis();
    queue<Cell> Q; Q.push(c);
    while (!Q.empty())
    {
        Cell now = Q.front(); Q.pop();
        v += now.volume();      //统计雕塑外围的总体积
        for (int i = 0; i < 6; i++)
        {
            Cell nxt = now.neighbor(i);
            if (!nxt.valid()) continue;     //越界
            if (nxt.solid()) s += now.area(i);      //统计雕塑外围表面积
            else if(!nxt.getVis())
            {
                nxt.setVis();
                Q.push(nxt);
            }
        }
    }
    v = maxc*maxc*maxc - v;     //雕塑体积 ＝＝ 整个空间的体积－雕塑外围体积
}
void discretize(int* x, int& n)     //对每一维进行离散化
{
    sort(x, x + n);
    n = (int)(unique(x, x+n) - x);
}
int ID(int* x, int n, int x0)   //找到原坐标离散化后的新坐标
{
    return (int)(lower_bound(x, x+n, x0) - x);
}
int main()
{
    int t; scanf("%d", &t);
    while (t--)
    {
        scanf("%d", &n);
        nx = ny = nz = 2;                //nx,ny,nz分别为三个方向上存的坐标数量
        xs[0] = ys[0] = zs[0] = 0;
        xs[1] = ys[1] = zs[1] = maxc;   //存入边界坐标
        for (int i = 0; i < n; i++)
        {
            scanf("%d%d%d", &x0[i], &y0[i], &z0[i]);
            scanf("%d%d%d", &x1[i], &y1[i], &z1[i]);
            x1[i] += x0[i], y1[i] += y0[i], z1[i] += z0[i];
            xs[nx++] = x0[i], xs[nx++] = x1[i];
            ys[ny++] = y0[i], ys[ny++] = y1[i];
            zs[nz++] = z0[i], zs[nz++] = z1[i];
        }
        discretize(xs, nx), discretize(ys, ny), discretize(zs, nz);//排序加去重
        memset(color, 0, sizeof(color));    //染色
        for (int i = 0; i < n; i++)   //对于每一个长方体，以左闭右开的方式标记，以点带体
        {
            int X1 = ID(xs, nx, x0[i]), X2 = ID(xs, nx, x1[i]);
            int Y1 = ID(ys, ny, y0[i]), Y2 = ID(ys, ny, y1[i]);
            int Z1 = ID(zs, nz, z0[i]), Z2 = ID(zs, nz, z1[i]);
            for (int X = X1; X < X2; X++)       //对离散化后的坐标依次染色
            {
                for (int Y = Y1; Y < Y2; Y++)
                {
                    for (int Z = Z1; Z < Z2; Z++)
                    {
                        color[X][Y][Z] = 1;
                    }
                }
            }
        }
        int s, v;
        floodfill(s, v);
        printf("%d %d\n", s, v);
    }
    return 0;
}