View Compilation Error

0_0_17024094_16947.cpp: In function 'void merge(int, int)':
0_0_17024094_16947.cpp:4:20: error: 'find' was not declared in this scope
     int t1 = find(x), t2 = find(y);
                    ^
0_0_17024094_16947.cpp:5:5: error: 'f' was not declared in this scope
     f[t1] = t2;
     ^
0_0_17024094_16947.cpp:5:13: error: 't2' was not declared in this scope
     f[t1] = t2;
             ^