View Compilation Error

0_0_36880424_2258.cpp: In function 'void solve()':
0_0_36880424_2258.cpp:46:3: error: 'flag' was not declared in this scope
   flag = 1;
   ^
0_0_36880424_2258.cpp:86:6: error: 'flag' was not declared in this scope
   if(flag) x = -x;
      ^