View Compilation Error

0_0_29242288_12180.cpp: In function 'int MANACHER(int*, int)':
0_0_29242288_12180.cpp:35:21: error: 'len' was not declared in this scope
             if(st[i-len[i]]==INF)
                     ^
0_0_29242288_12180.cpp:35:30: error: 'INF' was not declared in this scope
             if(st[i-len[i]]==INF)
                              ^