Common Mistakes

Mistake $1$: Forgetting to reset the visited array between DFS calls. This causes the algorithm to miss augmenting paths and return a suboptimal matching. Mistake $2$: Using the wrong graph structure (not bipartite).

Check for odd cycles first using BFS coloring. Mistake $3$: Off-by-one errors in indexing. Make sure your matching array and adjacency list indices match your input format ($0$-indexed vs $1$-indexed).