Minimum Number of Arrows to Burst Balloons

There are some spherical balloons taped onto a flat wall represented by the XY-plane. The balloons are represented as a 2D integer array `points` where `points[i] = [x_start, x_end]` denotes a balloon whose horizontal diameter stretches between `x_start` and `x_end`. Arrows can be shot up directly vertically (in the positive Y-direction) from different points along the X-axis. An arrow shot at `x` bursts all balloons whose `x_start <= x <= x_end`. Given the array `points`, return the minimum number of arrows that must be shot to burst all balloons. ### Constraints - `1 <= points.length <= 10^5` - `points[i].length == 2` - `-2^31 <= x_start < x_end <= 2^31 - 1` ### Input Format - Line 1: An integer `n` representing the number of balloons. - Next `n` lines: Two space-separated integers `x_start x_end`. ### Output Format Print the minimum number of arrows required.