View Compilation Error

0_0_37739329_8730.cpp:19:1: error: 'bitset' does not name a type
 bitset<2005>s[2005];
 ^
0_0_37739329_8730.cpp: In function 'void solve()':
0_0_37739329_8730.cpp:26:26: error: 's' was not declared in this scope
     for(int i=1;i<=n;i++)s[i].reset();
                          ^
0_0_37739329_8730.cpp:37:31: error: 'sort' was not declared in this scope
     sort(bian+1,bian+1+tot,cmp);
                               ^
0_0_37739329_8730.cpp:39:33: error: 's' was not declared in this scope
         if(!pre[bian[i].s])as+=(s[bian[i].x]^s[bian[i].y]).count();
                                 ^
0_0_37739329_8730.cpp:40:9: error: 's' was not declared in this scope
         s[bian[i].x][bian[i].y]=1;
         ^