Interval & Math Target: 15s
Sweep line converts intervals to +1/-1 events. Running sum gives concurrent count at any point. Alternative to heap approach.
events = []
for start, end in intervals:
events.append((start, 1)) # open
events.append((end, -1)) # close
events.sort()
cur = best = 0
for _, delta in events:
cur += delta
best = max(best, cur)Type it from memory. Go.