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  1. //Lib
  2. #include<cstdio>
  3. #include<cstring>
  4. #include<cstdlib>
  5. #include<cmath>
  6. #include<ctime>
  7.  
  8. #include<iostream>
  9. #include<algorithm>
  10. #include<vector>
  11. #include<string>
  12. #include<queue>
  13. #include<stack>
  14. #include<set>
  15. #include<map>
  16. using namespace std;
  17. //Macro
  18. #define rep(i,a,b)  for(int i=a,tt=b;i<=tt;++i)
  19. #define drep(i,a,b) for(int i=a,tt=b;i>=tt;--i)
  20. #define erep(i,e,x) for(int i=x;i;i=e[i].next)
  21. #define irep(i,x)   for(__typeof(x.begin()) i=x.begin();i!=x.end();i++)
  22. #define read()  (strtol(ipos,&ipos,10))
  23. #define sqr(x)  ((x)*(x))
  24. #define pb  push_back
  25. #define PS  system("pause");
  26. typedef long long   ll;
  27. typedef pair<int,int> pii;
  28. const int oo=~0U>>1;
  29. const double inf=1e100;
  30. const double eps=1e-6;
  31. string name="temp", in=".in", out=".out";
  32. //Var
  33. struct B
  34. {
  35.     int x,y,t;
  36.     bool operator<(const B &o)const{return t<o.t;}
  37. }bomb[50008];
  38. struct N
  39. {
  40.     int x,y;
  41.     N(){}
  42.     N(int x1,int y1):x(x1),y(y1){}
  43. };
  44. queue<N> q[2];
  45. int dx[]={0,0,1,-1},dy[]={1,-1,0,0};
  46. int n,m,ans;
  47. bool forbid[308][308],vis[308][308],safe[308][308];
  48. bool In(int x,int y){return !(x<0||x>n||y<0||y>n);}
  49. void Set(B u)
  50. {
  51.     int x=u.x,y=u.y,tx,ty;
  52.     forbid[x][y]=true;
  53.     forbid[x+1][y]=forbid[x][y+1]=true;
  54.     if(x)forbid[x-1][y]=true;
  55.     if(y)forbid[x][y-1]=true;
  56. }
  57. void Init()
  58. {
  59.     scanf("%d",&m);int x,y,t;
  60.     rep(i,1,m)
  61.     {
  62.         scanf("%d%d%d",&x,&y,&t);
  63.         bomb[i].x=x;bomb[i].y=y;bomb[i].t=t;
  64.         n=max(n,max(x,y));
  65.         Set(bomb[i]);       
  66.     }
  67.     n+=10;
  68.     sort(bomb+1,bomb+1+m);
  69.     rep(i,0,n)rep(j,0,n)if(!forbid[i][j])safe[i][j]=true;
  70.     memset(forbid,0,sizeof forbid);
  71. }
  72. void Work()
  73. {
  74.     int pos=1,now=1,tx,ty,x,y;
  75.     q[0].push(N(0,0));vis[0][0]=true;
  76.     N u;
  77.     while(!q[0].empty()||!q[1].empty())
  78.     {
  79.         for(++ans;bomb[pos].t==ans;Set(bomb[pos]),pos++);
  80.         now^=1;
  81.         while(!q[now].empty())
  82.         {
  83.             u=q[now].front();q[now].pop();
  84.             x=u.x,y=u.y;
  85.             rep(i,0,3)
  86.             {
  87.                 tx=x+dx[i];ty=y+dy[i];
  88.                 if(!In(tx,ty)||forbid[tx][ty])continue;
  89.                 if(safe[tx][ty])
  90.                 {
  91.                     printf("%d\n",ans);
  92.                     return;
  93.                 }
  94.                 else if(!vis[tx][ty])
  95.                 {
  96.                     vis[tx][ty]=true;
  97.                     q[now^1].push(N(tx,ty));
  98.                 }
  99.             }
  100.             vis[x][y]=false;
  101.         }
  102.     }
  103.     printf("-1\n");
  104. }
  105. int main()
  106. {
  107. //  freopen((name+in).c_str(),"r",stdin);
  108. //  freopen((name+out).c_str(),"w",stdout);
  109.     Init();
  110.     Work();
  111.     return 0;
  112. }
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https://ideone.com/OC4hR
language:
C++ (gcc 8.3)
created:
12 years ago
visibility:
public

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