View Compilation Error

0_0_30190798_15685.cpp: In function 'int Manacher()':
0_0_30190798_15685.cpp:29:65: error: 'l' was not declared in this scope
         while(s[i+p[i]] == s[i-p[i]] && i-p[i] >= 0 && i+p[i] < l)///判断半径外的字符还有没有相等的，如果有，就更新回文串的半径长
                                                                 ^