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;
}