Building Code

Here is the pseudocode:

for v = 1 to n:
 up[v][0] = parent[v]

for j = 1 to log(n):
 for v = 1 to n:
 up[v][j] = up[up[v][j-1]][j-1]

If up[v][j-1] is null or root, handle it (either set up[v][j] = root or leave it null).