i have seen some of the submission and even though there is editorial for this question but i am not getting in anyway , can anybody help please?

**The first observation is that the answer cannot be greater than the n.**

suppose we can perform **i operations** on the k-arrays then we have to find minimum and maximum value possible for each k-arrays.

we can find it greedily by **first sort all the k-arrays** then -

->the minimum value is calculated by change all the i maximum element to L and sum up the array

->the maximum value is calculated by change all the i minimum element to R and sum up the array

**example** suppose L = 4, R = 7 array = [4, 5, 6, 7, 7];

For 3 operations

we get minimum sum by replace last 3 elements by **L** (6 ,7 ,7 by 4 ,4 ,4) and in this way we get minimum sum which equal to 21

we get maximum sum by replace first 3 elements by **R** (4 ,5 ,6 by 7 ,7 ,7) and in this way we get maximum sum which equal to 35

we do this operation for all k-arrays and store the min and max value for given operation and **if all ranges have common point then the answer is**

**possible else not.**

so the remaining task is to perform **binary search on number of operations**, if for the given **MID** the answer is possible then go for lower_bound else go for upper_bound.

Time Complexity = (NKlog(N) + Klog(N))

my submission link CodeChef: Practical coding for everyone