View Compilation Error

0_0_25647511_27610.cpp: In function 'void init()':
0_0_25647511_27610.cpp:10:15: error: 'M' was not declared in this scope
     for(i=0;i<M;++i)
               ^
0_0_25647511_27610.cpp:12:9: error: 'father' was not declared in this scope
         father[i]=i;
         ^
0_0_25647511_27610.cpp: In function 'int find(int)':
0_0_25647511_27610.cpp:19:8: error: 'father' was not declared in this scope
     if(father[x]!=x)
        ^
0_0_25647511_27610.cpp:21:12: error: 'father' was not declared in this scope
     return father[x];
            ^
0_0_25647511_27610.cpp: In function 'void merge(int, int)':
0_0_25647511_27610.cpp:30:5: error: 'father' was not declared in this scope
     father[y]=x;
     ^