Suppose we have a list of non-overlapping intervals. These are sorted based on end time. We have another interval target, find final interval after merging target so that intervals are still non-overlapping and sorted.
So, if the input is like intervals = [[1, 15],[25, 35],[75, 90]], target = [10, 30], then the output will be [[1, 35], [75, 90]] as first two intervals [1, 15] and [25, 35] are merged.
To solve this, we will follow these steps −
insert target at the end of iv
sort iv based on start time
res := a new list with first interval
i := 1
while i < size of iv, do
if start time of iv[i] <= end time of last interval of res, then
end time of last interval of res = maximum of (end time of last interval of res and end time of iv[i])
otherwise,
insert iv[i] at the end of res
i := i + 1
return res
Example (Python)
Let us see the following implementation to get a better understanding −
class Solution: def solve(self, iv, target): iv.append(target) iv.sort(key=lambda x: x[0]) res = [iv[0]] i = 1 while i < len(iv): if iv[i][0] <= res[-1][1]: res[-1][1] = max(res[-1][1], iv[i][1]) else: res.append(iv[i]) i += 1 return res ob = Solution() intervals = [ [1, 15], [25, 35], [75, 90] ] target = [10, 30] print(ob.solve(intervals, target))
Input
[[1, 15],[25, 35],[75, 90]], [10, 30]
Output
[[1, 35], [75, 90]]