Minimum Triggers to Absorb All Balls (Connected Components by Row/Column Within Distance)

You are given n balls on a 2D plane with coordinates (x[i], y[i]). Two balls are directly connected if and only if either: they share the same row (same y) and |x1 - x2| <= d, or they share the same column (same x) and |y1 - y2| <= d. Connectivity is transitive: balls in the same connected component will be absorbed together. In one trigger, you may pick any not-yet-absorbed ball; then the entire connected component containing it gets absorbed. Find the minimum number of triggers needed to absorb all balls. Input: n, d n lines of x[i], y[i] Output: minimum triggers (number of connected components). Example Input 1 3 0 0 Output 1