On friday I participated in the round 1A of the GCJ but I could not pass the third problem. Even the easy set test. Here are my two codes.
In the easy one, I just did what the editorial said. However, I got WA repeatedly (15 submissions).
For the full set, my idea is the following. First rest from P the perimeter of all the rectangles and now I have P'. Now, each rectangle i add to the answer 0 if it is not cut, or a number in range
[ L[i], R[i] ] where
L[i] = 2 * min (W[i], H[i]) and
R[i] = 2 * hypot (W[i], H[i]) if is cut. The idea is to choose a subset of the rectangles whom will be cut and the sum of additional perimeters must not exceed P'.
Now, each subset j generates an interval
[ L_subset[j], R_subset[j] ]. However, these intervals will always start (left side value) with at most
250 * 100 (maximum side length and maximum quantity of rectangles). Therefore, I did a DP where
DP[i] is the maximum right side of an interval for the left side be exactly i.
Start DP[i] = -INF DP = 0 FOR i in range(0, N): FOR leftside in range(0,25001) DP[leftside] = max (DP[leftside] , DP[leftside – L[i] ] + R[i] )
Now, for each
i <= P' I checked if
DP[i] >= P', then the answer is P as this could be reached. Otherwise, the answer is
max DP[i] for
i <= P' plus the sum of perimeters of all rectangles.
The complexity of this idea is 100 * 100 * 250. Could give TLE, I don't know because the system always gave me WA.
I spend all the weekend tring to find out why my codes gave me WA, now I need your help. Many thanks