Time limit
2s
Memory limit
128 MB
Guitarist Kangto will play N songs in a fixed order during a concert. For this concert, the volume may be changed only right before each song starts.
Before the concert, an array V of length N was prepared. V[i] means that, before the i-th song starts, the current volume must be changed by exactly V[i], either up or down. If the current volume is P, then the i-th song can only be played at volume P + V[i] or P - V[i].
The volume must always be between 0 and M, inclusive. It cannot be changed to a value outside this range.
Given the number of songs N, the starting volume S, the maximum volume M, and the array V, find the maximum volume at which the last song can be played. The songs must be played in the given order.
The first line contains N, S, and M. (1 <= N <= 50, 1 <= M <= 1,000, 0 <= S <= M)
The second line contains the volume differences V[1], V[2], ..., V[N] that must be applied before each song starts. Each value is between 1 and M, inclusive.
Print the maximum possible volume for the last song. If it is impossible to reach the last song, print -1.
No additional hints are provided.