dijistra最短路 hdu1242 Rescue

#include<cstdio>
#include<cmath>
#include<cstring>
#include<queue>
#include<stack>
#include<vector>
#include<functional>
#include<algorithm>

using namespace std;
typedef long long LL;
typedef pair<int, int> PII;

const int MX = 200 + 5;
const int INF = 0x3f3f3f3f;
int vis[MX][MX];
char S[MX][MX];
int dist[][2] = {{1, 0}, { -1, 0}, {0, 1}, {0, -1}};

struct Point {
int x, y, t;
Point(int a, int b, int c) {
x = a;
y = b;
t = c;
}
bool operator<(const Point &b)const {
return t > b.t;
}
};

int main() {
int m, n;
while(~scanf("%d%d", &m, &n)) {
memset(vis, INF, sizeof(vis));

Point FST(-1, -1, 0);
for(int i = 1; i <= m; i++) {
scanf("%s", S[i] + 1);
for(int j = 1; j <= n; j++) {
if(S[i][j] == 'r') {
FST = Point(i, j, 0);
}
}
}

if(FST.x == -1) {
printf("Poor ANGEL has to stay in the prison all his life.\n");
continue;
}

priority_queue<Point>work;
work.push(FST);

int ans = INF;
while(!work.empty()) {
Point fp = work.top();
work.pop();

vis[fp.x][fp.y] = fp.t;
if(S[fp.x][fp.y] == 'a') {
ans = fp.t;
break;
}

for(int k = 0; k < 4; k++) {
int nx = fp.x + dist[k][0];
int ny = fp.y + dist[k][1];
if(nx < 1 || nx > m || ny < 1 || ny > n) continue;
if(S[nx][ny] == '#') continue;

if(S[nx][ny] == '.' || S[nx][ny] == 'a') {
if(vis[nx][ny] > fp.t + 1) {
vis[nx][ny] = fp.t + 1;
work.push(Point(nx, ny, fp.t + 1));
}
} else if(vis[nx][ny] > fp.t + 2) {
vis[nx][ny] = fp.t + 2;
work.push(Point(nx, ny, fp.t + 2));
}
}
}

if(ans == INF) {
printf("Poor ANGEL has to stay in the prison all his life.\n");
continue;
} else {
printf("%d\n", ans);
}
}
return 0;
}