View Compilation Error

0_0_19792444_12375.cpp: In function 'void solve()':
0_0_19792444_12375.cpp:23:37: error: 'v1' was not declared in this scope
         ld at=sqrt(300*300+mid*mid)/v1,at2=(300+mid)/v2;
                                     ^
0_0_19792444_12375.cpp:24:16: error: 'at2' was not declared in this scope
         if(at<=at2) r=mid;
                ^
0_0_19792444_12375.cpp:28:21: error: 'v1' was not declared in this scope
       ld t3=(l+600)/v1,t4=(600-l)/v2+T;
                     ^
0_0_19792444_12375.cpp:29:14: error: 't4' was not declared in this scope
       if(t3<=t4) puts("Yes");
              ^