10
-405 -230 252 -393 -390 -259 97 163 81 -129
 3
10000 -10000 10000
 1
-10000
 20
-16 -23 29 44 -40 -50 -41 34 -38 30 -12 28 -44 -49 15 50 -28 38 -2 0

702.333333333333712
 10000.000000000016371
 0.000000000000000
 113.875000000000043

n=int(input())
l=list(map(int,input().split()))
mi=min(l)
ma=max(l)
s=(mi+ma)/2
for i in range(n): l[i]-=s
s=ma=mi=0
for x in l:
    s+=x
    if s<0: s=0
    if s>ma: ma=s
s=0
for x in l:
        s-=x
        if s<0: s=0
        if s>mi: mi=s
print("%.6f"%max(mi,ma))
    
