#include<cstdio>
#include<cstring>
#include<iostream>
#include<queue>
#include<vector>
using namespace std ;
const int maxn = 130;
const int inf = 0x7fffffff;
int N;
int dx[4] = {-1,0,1,0};
int dy[4] = {0,1,0,-1};
int line[maxn][maxn];
int vis[maxn][maxn];
int ans = inf;
struct node
{
int x,y;
int sum ;
};
struct cmp{
bool operator ()(struct node &a,struct node &b){
return a.sum>b.sum;//最小值优先
}
};
void bfs()
{
priority_queue<struct node,vector<struct node>,cmp> que;
struct node first = {1,1,line[1][1]};
vis[1][1] = 1;
que.push(first);
while(que.size())
{
struct node now = que.top();
que.pop();
if(now.sum > ans)
continue ;
if(now.x == N &&now.y == N)
ans = min(ans,now.sum);
for(int i = 0;i < 4;i++)
{
int x1 = now.x + dx[i] ;
int y1 = now.y + dy[i] ;
if(!vis[x1][y1]&&(x1>=1)&&(x1<=N)&&(y1>=1)&&(y1<=N))
{
struct node next={x1,y1,line[x1][y1]+now.sum};
vis[x1][y1] = 1;
que.push(next);
}
}
}
}
int main()
{
// freopen("in.txt","r",stdin);
int cas = 0;
while(scanf("%d",&N)&&N)
{
for(int i = 1 ;i <= N ;i++)
for(int j = 1;j <= N ;j++)
scanf("%d",&line[i][j]);
ans = inf ;
memset(vis,0,sizeof(vis));
bfs();
printf("Problem %d: ",++cas);
printf("%d\n",ans);
}
return 0;
}
hdu 3152Obstacle Course bfs+优先队列
原文：http://blog.csdn.net/cq_pf/article/details/44596389
