from random import randint
n = int(input())
a = list(map(int,input().split()))
def brut(n,a):
m=0
for i in range(n):
s=1
h=a[i]
for j in range(1,n):
if a[(i+j)%n]>h:
h=a[(i+j)%n]
s += 1
if s>m:
m=s
return m
def efi(n,a1):
stos = []
a = 2*a1[:]
P = [0]*n
#print("a",a[:n])
for i in range(2*n-1,-1,-1):
while stos and a[stos[-1]]<=a[i]:
j = stos.pop()
if j-i<=n:
P[j%n] = i%n
else:
P[j%n] = j%n
while stos and stos[-1]-i>n:
stos.pop()
P[j%n] = j%n
stos.append(i)
#print("P",P)
d = [0]*(n+1)
for i in range(n):
if P[i]<i:
d[P[i]+1] += 1
d[i+1] -=1
elif P[i]==i:
d[0] += 1
d[n] -= 1
else:
d[0] += 1
d[i+1] -= 1
d[P[i]+1] +=1
d[n] -= 1
#print("d",d)
s = [d[0]]
m = s[0]
for i in range(1,n):
s.append(s[i-1]+ d[i])
m = max(s[i],m)
#print(s)
return m
print(efi(n,a))
#print(brut(n,a))
# for i in range(100):
# n=20
# a=[randint(1,9) for _ in range(n)]
# b = brut(n,a)
# e = efi(n,a)
# if b!=e:
# print(a,b,e)
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 | from random import randint n = int(input()) a = list(map(int,input().split())) def brut(n,a): m=0 for i in range(n): s=1 h=a[i] for j in range(1,n): if a[(i+j)%n]>h: h=a[(i+j)%n] s += 1 if s>m: m=s return m def efi(n,a1): stos = [] a = 2*a1[:] P = [0]*n #print("a",a[:n]) for i in range(2*n-1,-1,-1): while stos and a[stos[-1]]<=a[i]: j = stos.pop() if j-i<=n: P[j%n] = i%n else: P[j%n] = j%n while stos and stos[-1]-i>n: stos.pop() P[j%n] = j%n stos.append(i) #print("P",P) d = [0]*(n+1) for i in range(n): if P[i]<i: d[P[i]+1] += 1 d[i+1] -=1 elif P[i]==i: d[0] += 1 d[n] -= 1 else: d[0] += 1 d[i+1] -= 1 d[P[i]+1] +=1 d[n] -= 1 #print("d",d) s = [d[0]] m = s[0] for i in range(1,n): s.append(s[i-1]+ d[i]) m = max(s[i],m) #print(s) return m print(efi(n,a)) #print(brut(n,a)) # for i in range(100): # n=20 # a=[randint(1,9) for _ in range(n)] # b = brut(n,a) # e = efi(n,a) # if b!=e: # print(a,b,e) |
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