Minimum Arrows - Walkthrough

Balloons: [[10,16], [2,8], [1,6], [7,12]]. Sorted by end: [[1,6], [2,8], [7,12], [10,16]]. $1.$ Arrow $1$ at position $6$. Bursts [1,6] and [2,8] (both contain $6$). Remaining: [7,12], [10,16].

$2.$ Arrow $2$ at position $12$. Bursts [7,12] and [10,16] (both contain $12$). Remaining: none. Total arrows: $2$. Notice [2,8] and [7,12] do not overlap (gap at 6-7), so they need separate arrows. The key is finding where one group ends and another begins. Each arrow represents a maximal group of overlapping balloons.