hdu 1026【Ignatius and the Princess I】

广搜

我用path记录路径，初始为-1，并且可以用path标记该点是否走过，如果为-1则表示没有走过，一举两得，然后用print递归输出路径。在记录路径时我是将点的坐标转化为一个数值即X*M+Y，当输出路径的时候可将path里面的值转化为坐标……

#include <iostream>
#include <queue>
#include <cstdio>
using namespace std;

const int maxlen = 100 + 10;
struct place 
{
    int x,y;
    int step;
    friend bool operator <(place a,place b)
    {
        return a.step > b.step;
    }
};
int path[maxlen][maxlen];
char map[maxlen][maxlen];
int N,M;
int dirx[4] = {-1,0,1,0};
int diry[4] = {0,-1,0,1};

int bfs()
{
    priority_queue<place> q;
    place Start;
    Start.x = 0;
    Start.y = 0;
    Start.step = 0;
    q.push(Start);
    path[0][0] = 0;
    while(!q.empty())
    {
        place temp = q.top();
        q.pop();
        if(temp.x == N - 1 &&temp.y == M -1)
        {
            return temp.step;
        }

        place tmp;
        for(int i = 0;i < 4;i ++)
        {
            int rx = temp.x + dirx[i];
            int ry = temp.y + diry[i];
            if(rx < 0 || rx >= N || ry < 0 || ry >= M)
                continue;

            if(map[rx][ry] == '.'&&path[rx][ry] == -1)
            {
                tmp.x = rx;
                tmp.y = ry;
                tmp.step = temp.step + 1;
                path[rx][ry] = temp.x * M + temp.y;
                q.push(tmp);
            }
            if(map[rx][ry] != '.'&&map[rx][ry] != 'X' && path[rx][ry] == -1)
            {
                tmp.x = rx;
                tmp.y = ry;
                int num = map[rx][ry] - '0';
                tmp.step = temp.step + num + 1;
                path[rx][ry] = temp.x * M + temp.y;
                q.push(tmp);
            }
        }

    }

    return -1;
}

void print(int x,int y,int s)
{
    if(x == 0 && y == 0)
    {
        //cout << s <<"s:(0,0)->";
        return;
    }
    int rx = path[x][y] / M;
    int ry = path[x][y] % M;
    if(map[x][y] != '.' && map[x][y] != 'X')
    {
        int num = map[x][y] - '0';
        print(rx,ry,s - num - 1);
        cout << s-num << "s:(" << rx << "," << ry <<")->";
        cout << "(" <<x << "," <<y <<")" <<endl;
        for(int i = 0;i < num;i ++)
        {
        cout << s -num +1+i <<"s:FIGHT AT (" <<x <<","<<y <<")" << endl;
        }
    }
    else if(map[x][y] == '.')
    {
        print(rx,ry,s-1);
        cout << s << "s:(" << rx << "," << ry <<")->";
        cout << "(" <<x << "," <<y <<")" <<endl;
    }
}

            
int main()
{
    while(cin >> N >> M)
    {
        memset(path,-1,sizeof(path));
        for(int i = 0;i < N;i ++)
        {
            for(int j = 0;j < M;j ++)
            {
                cin >> map[i][j];
            }
        }

        int ans = bfs();
        if(ans == -1)
        {
            cout << "God please help our poor hero." << endl;
        }
        else
        {
            cout << "It takes " << ans << " seconds to reach the target position, let me show you the way." << endl;
            print(N-1,M-1,ans);
        }
        cout << "FINISH" << endl;
    }

    return 0;
}