ural 1119 Metro

http://acm.timus.ru/problem.aspx?space=1&num=1119

 #include <cstdio>
 #include <cstring>
 #include <queue>
 #include <cmath>
 #include <algorithm>
 #define maxn 1010
 using namespace std;

 int head[maxn],e,n,m;
 int dir[][]={{,-},{,},{,},{-,}};
 bool vis[maxn][maxn];
 bool visi[maxn][maxn];
 double step;

 struct node
 {
     int x,y;
     double step;
 }st,st1,st2;

 void bfs(node st)
 {
     queue<node>q;
     st.step=0.0;
     q.push(st);
     memset(visi,false,sizeof(visi));
     visi[st.x][st.y]=true;
     while(!q.empty())
     {
         st1=q.front();
         q.pop();
         if(st1.x==m&&st1.y==n) {step=st1.step;return;}
         for(int i=; i<; i++)
         {
             int xx=st1.x+dir[i][];
             int yy=st1.y+dir[i][];
             if(xx>=&&xx<=m&&yy>=&&yy<=n&&!visi[xx][yy])
             {
                 st2.step=st1.step+100.0;
                 visi[xx][yy]=true;
                 st2.x=xx;
                 st2.y=yy;
                 q.push(st2);
             }
         }
         if(vis[st1.x+][st1.y+]&&st1.x+<=m&&st1.y+<=n&&st1.x+>=&&st1.y+>=)
         {
             vis[st1.x+][st1.y+]=true;
             st2.x=st1.x+;
             st2.y=st1.y+;
             st2.step=st1.step+sqrt()*100.0;
             q.push(st2);
         }
     }
 }
 int main()
 {
     int k,a,b;
     step=;
     scanf("%d%d",&n,&m);
     scanf("%d",&k);
     memset(vis,false,sizeof(vis));
     for(int i=; i<=k; i++)
     {
         scanf("%d%d",&a,&b);
         vis[b][a]=true;
     }
     st.x=;
     st.y=;
     bfs(st);
     printf("%.0lf\n",step);
     return ;
 }