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  • poj2049

    优先队列广搜,有人说用SPFA,不知道怎么做的

    #include <cstdio>
    #include <queue>
    #include <cmath>
    #include <cstring>
    #include <cstdlib>
    using namespace std;
    
    #define MAX_COORDINATE 205
    #define inf 0x3f3f3f3f
    #define EDGE 200
    
    struct Grid
    {
        int left, right, up, down;
    }grid[MAX_COORDINATE][MAX_COORDINATE]; // using down-left coner point to present a gird
    
    struct Point
    {
        int x, y;
        int door_cnt;
        Point()
        {}
        Point(int xx, int yy, int dd):x(xx), y(yy), door_cnt(dd)
        {}
    }nemo;
    
    int wall_num, door_num;
    bool vis[MAX_COORDINATE][MAX_COORDINATE];
    
    bool operator < (const Point &a, const Point &b)
    {
        return a.door_cnt > b.door_cnt;
    }
    
    void make_grids(int x, int y, int direction, int value)
    {
        if (direction == 0)
        {
            grid[x][y].down = value;
            grid[x][y - 1].up = value;
        }else
        {
            grid[x][y].left = value;
            grid[x - 1][y].right = value;
        }
    }            
    
    void build_wall(int x, int y, int direction, int length)
    {
        for (int i = 0; i < length; i++)
        {
            int current_x = x;
            int current_y = y;
            if (direction == 0)
                current_x += i;
            else
                current_y += i;
            make_grids(current_x, current_y, direction, inf);
        }
    }
    
    void init_grids()
    {
        for (int i = 0; i < EDGE; i++)
        {
            grid[i][0].down = inf;
            grid[i][EDGE - 1].up = inf;
            grid[0][i].left = inf;
            grid[EDGE - 1][i].right = inf;
        }
    }
    
    void input()
    {
        memset(grid, 0, sizeof(grid));
        init_grids();
        for (int i = 0; i < wall_num; i++)
        {
            int x, y, direction, length;
            scanf("%d%d%d%d", &x, &y, &direction, &length);
            build_wall(x, y, direction, length);
        }
        for (int i = 0; i < door_num; i++)
        {
            int x, y, direction;
            scanf("%d%d%d", &x, &y, &direction);
            make_grids(x, y, direction, 1);
        }
        double x, y;
        scanf("%lf%lf", &x, &y);
        nemo.x = floor(x);
        nemo.y = floor(y);
    }
    
    int work()
    {
        if (nemo.x < 0 || nemo.x >= EDGE || nemo.y < 0 || nemo.y >= EDGE)
            return 0;
        priority_queue<Point> pq;
        pq.push(Point(0, 0, 0));
        memset(vis, 0, sizeof(vis));
        vis[0][0] = true;
        while (!pq.empty())
        {
            Point u = pq.top();
            if (u.x == nemo.x && u.y == nemo.y)
                return u.door_cnt;
            pq.pop();
            if (grid[u.x][u.y].up != inf && !vis[u.x][u.y + 1])
            {
                pq.push(Point(u.x, u.y + 1, u.door_cnt + grid[u.x][u.y].up));
                vis[u.x][u.y + 1] = true;
            }
            if (grid[u.x][u.y].down != inf && !vis[u.x][u.y - 1])
            {
                pq.push(Point(u.x, u.y - 1, u.door_cnt + grid[u.x][u.y].down));
                vis[u.x][u.y - 1] = true;
            }
            if (grid[u.x][u.y].left != inf && !vis[u.x - 1][u.y])
            {
                pq.push(Point(u.x - 1, u.y, u.door_cnt + grid[u.x][u.y].left));
                vis[u.x - 1][u.y] = true;
            }
            if (grid[u.x][u.y].right != inf && !vis[u.x + 1][u.y])
            {
                pq.push(Point(u.x + 1, u.y, u.door_cnt + grid[u.x][u.y].right));
                vis[u.x + 1][u.y] = true;
            }
        }
        return -1;
    }
    
    int main()
    {
        while (scanf("%d%d", &wall_num, &door_num), !(wall_num == -1 && door_num == -1))
        {
            input();
            printf("%d
    ", work());
        }
        return 0;
    }
    View Code
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  • 原文地址:https://www.cnblogs.com/rainydays/p/3266050.html
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