View Compilation Error

0_0_30241186_1981.cpp: In function 'int find(int)':
0_0_30241186_1981.cpp:37:11: error: 'per' was not declared in this scope
     while(per[r] != r)
           ^
0_0_30241186_1981.cpp:39:5: error: 'per' was not declared in this scope
     per[x] = r;
     ^