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# 452. Minimum Number of Arrows to Burst Balloons
"""
there are some spherical balloons taped onto a flat wall that represents the
xy plane. the ballooons are represented as a 2d integer array 'points' where
'points[i] = [x_start, x_end]'. you do not know the exact y coordinates of
the balloons. arrows can be shot up directly vertically in the positive y
direction. from different points along the x axis. given the array points,
return the minimum number of arrows that must be shot to burst all balloons.
"""
class Solution(object):
def findMinArrowShots(self, points):
"""
:type points: List[List[int]]
:rtype: int
"""
points.sort(key=lambda p: p[1])
ans, arrow = 0, 0
for [start, end] in points:
if ans == 0 or start > arrow:
ans, arrow = ans + 1, end
return ans
if __name__ == "__main__":
obj = Solution()
print(obj.findMinArrowShots(points=[[10, 16], [2, 8], [1, 6], [7, 12]]))
print(obj.findMinArrowShots(points=[[1, 2], [3, 4], [5, 6], [7, 8]]))
print(obj.findMinArrowShots(points=[[1, 2], [2, 3], [3, 4], [4, 5]]))
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