HDU 1242(bfs)-蒲公英云

HDU 1242(bfs)

题意：一个朋友拯救angel，’a’ 是angel， ‘x’是士兵， ‘r’是朋友，’#‘是墙壁。没走一步花费一个单位的时间，遇到士兵与士兵搏斗花费一个单位的时间，求最短时间。

#include <iostream>
#include <queue>
#include <string>
#include <sstream>
using namespace std;
struct Point
{
    int x, y, time;
    bool operator <(const Point& rhs) const
    {
        return time > rhs.time;
    }
} a;
int direction[4][2] = { {1, 0}, {-1, 0}, {0, -1}, {0, 1} };
void getXY(string* matrix, int n, int m)
{
    for (int i = 1; i <= n; ++i)
        for (int j = 1; j <= m; ++j)
            if (matrix[i][j] == 'a')
            {
                a.x = i;
                a.y = j;
                a.time = 0;
                return;
            }
}
int result(string* matrix)
{
    Point t;
    priority_queue<Point> q;
    Point p;
    q.push(a);
    while (!q.empty())
    {
        p = q.top();
        q.pop();
        for (int i = 0; i < 4; ++i)
        {
            t.x = p.x + direction[i][0];
            t.y = p.y + direction[i][1];
            if (matrix[t.x][t.y] == '#')
                continue;
            t.time = p.time + 1;
            if (matrix[t.x][t.y] == 'r')
                return t.time;
            if (matrix[t.x][t.y] == 'x')
                t.time += 1;
            matrix[t.x][t.y] = '#';
            q.push(t);
        }
    }
    return -1;
}
int main()
{
    int n, m, i;
    string line;
    string matrix[202];
    while (cin >> n >> m)
    {
        getchar();
        for (i = 1; i <= n; ++i)
        {
            getline(cin, matrix[i]);
            matrix[i] = '#' + matrix[i] + '#';
        }
        matrix[n+1] = matrix[0] = string(m+2, '#');
        getXY(matrix, n, m);
        i = result(matrix);
        if (i == -1)
            cout << "Poor ANGEL has to stay in the prison all his life.\n";
        else cout << i << endl;
    }
}