View Compilation Error

0_0_21596271_21984.cpp: In function 'int Find(int)':
0_0_21596271_21984.cpp:3:15: error: 'tree' was not declared in this scope
           if (tree[x].parent != x)
               ^
0_0_21596271_21984.cpp:7:18: error: 'tree' was not declared in this scope
           return tree[x].parent;
                  ^
0_0_21596271_21984.cpp: In function 'void Merge(int, int, int, int, int)':
0_0_21596271_21984.cpp:12:15: error: 'tree' was not declared in this scope
           if (tree[q].depth > tree[p].depth) tree[p].parent = q;
               ^