hdu 3152 Obstacle Course

bfs+优先队列，无难度

#include<iostream>
#include<queue>
#include<cstring>
#define maxn 125+5
using namespace std;
int n;
int casee=1;
int mapp[maxn][maxn];
int visit[maxn][maxn];
int dir[4][2]={{0,1},{0,-1},{1,0},{-1,0}};
struct stu
{
	int x,y;
	int sum;
	friend bool operator<(stu x,stu y)
	{
		return x.sum>y.sum;
	}
};
void bfs()
{
	stu x,y;
	priority_queue<stu>root;
	x.x=0;
	x.y=0;
	x.sum=mapp[0][0];
	visit[0][0]=1;
	root.push(x);
	while(root.size())
	{
		x=root.top();
		root.pop();
		if(x.x==n-1&&x.y==n-1){cout<<"Problem "<<casee++<<": "<<x.sum<<endl;return;}
		for(int i=0;i<4;i++)
		{
			y.x=x.x+dir[i][0];
			y.y=x.y+dir[i][1];
			if(y.x<0||y.x>=n||y.y<0||y.y>=n||visit[y.x][y.y]){continue;}
			y.sum=x.sum+mapp[y.x][y.y];
			root.push(y);
			visit[y.x][y.y]=1;
		}
	}
}
int main()
{
	while(cin>>n&&n)
	{
		for(int i=0;i<n;i++)
		{
			for(int j=0;j<n;j++)
			{
				cin>>mapp[i][j];
			}
		}
		memset(visit,0,sizeof(visit));
		bfs();
	}
	return 0;
}