上海金马五校程序设计竞赛 Problem B : Sailing

题目链接 http://acm.dhu.edu.cn/contest/view.html?id=875&index=1
优先队列，步数相同的，*号优先

#include<stdio.h>
#include<time.h>
#include<cmath>
#include <iostream>
#include<string.h>
#include <set>
#include <queue>
using namespace std;
typedef long long ll;
const int maxn = 21;
char a[55][55];
class Node{
public :
int x;int y;int d;
Node(int a, int b, int c):x(a),y(b),d(c){}
};
bool operator < (const Node &t1, const Node&t2)
{
return t1.d > t2.d||(t1.d==t2.d&&((a[t1.x][t1.y]==a[t2.x][t2.y])||(a[t1.x][t1.y]=='#'&&a[t2.x][t2.y]=='*'))); // 按照z的顺序来决定t1和t2的顺序
}
int dx[4]={-1,0,1,0};
int dy[4]={0,-1,0,1};
int res[55][55];
int main()
{
int n;
priority_queue<Node> q;
while(scanf("%d",&n)!=EOF){
memset(res, 0, sizeof(res));
// cout<<n<<endl;
while(!q.empty()){
q.pop();
}
for(int i=0;i<n;i++)
for(int j=0;j<n;j++){
cin>>a[i][j];
}
// for(int i=0;i<n;i++)
// for(int j=0;j<n;j++){
// cout<<a[i][j];
// }
q.push(Node(0,0,0));
res[0][0] = 1;
int tx,ty,td;
while (!q.empty()){
Node t = q.top();
q.pop();
// cout<<t.x<<" "<<t.y<<" "<<t.d<<endl;
if(t.x==n-1&&t.y==n-1){
cout<<t.d<<endl;break;
}
for(int i=0;i<4;i++){
tx = t.x+dx[i];
ty = t.y+dy[i];
td = t.d;
if(res[tx][ty]==0&&tx>=0&&ty>=0&&tx<n&&ty<n){
res[tx][ty]=1;
if(a[t.x][t.y]=='#'||a[tx][ty]=='#')
td++;
q.push(Node(tx,ty,td));
// cout<<tx<<" "<<ty<<" "<<td<<endl;
}
}
}
}
return 0;
}