Planet Cycles - Walkthrough

Graph: $f(1) = 2, f(2) = 3, f(3) = 1, f(4) = 2$. You need to find the answer for each node. The answer is the total path length until returning to a cycle. Start DFS at $1$: path $[1, 2, 3]$, next is $1$ (in path). Cycle detected with length $3$. Assign $3$ to nodes $1$, $2$, $3$.

All cycle nodes get the cycle length as their answer. Start DFS at $4$: path $[4]$, next is $2$ (already processed with answer $3$). Node $2$ has answer $3$. Node $4$ is $1$ step from the cycle, so answer is $1 + 3 = 4$. Tail nodes add their distance.