Common Mistakes

Mistake $1$: Looping $i$, $j$, $k$ instead of $k$, $i$, $j$. This breaks the DP dependency and gives wrong answers. Mistake $2$: Forgetting dist[i][i] = 0. This makes the algorithm think the distance from $i$ to itself is infinity.

Mistake $3$: Not checking for negative cycles before using $dist$ values. If dist[i][i] < 0, the entire distance matrix is invalid. These are the most common errors when implementing Floyd-Warshall.