View Compilation Error

0_0_17512596_27045.cpp: In function 'bool ok(int)':
0_0_17512596_27045.cpp:12:14: error: 'inf' was not declared in this scope
     ma1=ma2=-inf;
              ^
0_0_17512596_27045.cpp:16:12: error: 'b' was not declared in this scope
         if(b[i]-a[i]>mid)
            ^
0_0_17512596_27045.cpp:16:17: error: 'a' was not declared in this scope
         if(b[i]-a[i]>mid)
                 ^