def LargestRectangleInHistogram(hist):
s = Stack()
i = 0
max_area = 0
# Scan through Histogram
while i < len(hist):
# Increasing ---> Current Hist > Prev Hist
if s.isEmpty() or hist[i] >= hist[s.peek()]:
s.push(i)
# Decreased! ---> Current Hist < Prev Hist (Hisab lagavi do)
else:
# Pop hist till Decreasing stops
while not s.isEmpty() and hist[s.peek()] > hist[i]:
L = s.pop()
height = hist[L]
if s.isEmpty():
area = height * i
else:
area = height * (i - s.peek() - 1)
max_area = max(max_area, area)
s.push(i)
i += 1
while not s.isEmpty():
L = s.pop()
height = hist[L]
area = height * (i - L - 1)
max_area = max(max_area, area)
return max_area
def sort_stack(src):
result = Stack()
while not src.isEmpty():
item = src.pop()
while not result.isEmpty() and item > result.peek():
src.push(result.pop())
result.push(item)
return result
def Nearest_Smallest(arr):
result = [-1] * len(arr)
s = Stack()
s.push(-1)
# Scan through entire Array
for index in xrange(len(arr)):
# Nearest value is lesser ? Choose it
if arr[index] > s.peek():
result[index] = s.peek()
else:
# Go till the prev nearest value that's lesser? Choose it
while arr[index] > s.peek():
s.pop()
result[index] = s.peek()
# Get ready for next iteration
s.push(arr[index])
return result
def LargestRectangleInHistogram_optimized(hist):
s = Stack()
max_area = 0
i = 0
# Scan through Histogram
while i < len(hist):
# Increasing ---> Current Hist > Prev Hist
if s.isEmpty() or hist[i] >= hist[s.peek()]:
s.push(i)
i += 1
# Decreased! ---> Current Hist < Prev Hist (Hisab lagavi do)
else:
# Pop hist till Decreasing stops
L = s.pop()
# Calculate area
if s.isEmpty():
current_area = hist[L] * i
else:
current_area = hist[L] * (i - s.peek() - 1)
# Hisab for max area
max_area = max(max_area, current_area)
# Consider all remaining histogram
while not s.isEmpty():
L = s.pop()
# Calculate area
if s.isEmpty():
current_area = hist[L] * i
else:
current_area = hist[L] * (i - s.peek() - 1)
# Hisab for max area
max_area = max(max_area, current_area)
return max_area
def main():
str = "AppleKayaKnothingAvid divA"
mystack = Stack()
mystack.push(str[0])
ele = []
for i in xrange(1, len(str) - 1):
if str[i + 1] == mystack.peek():
ele.append(mystack.pop())
else:
mystack.push(str[i])
total = mystack.size()
end = len(str) - 1
print "Palindrom strings:"
for i in range(total):
palindrom = ""
temp = mystack.pop()
while str[end] != temp:
palindrom += str[end]
end -= 1
print palindrom
end -= 1
def main():
str = "what is avid diva when kayak agree"
mystack = Stack()
mystack.push(str[0])
mymap = {}
PalindromStartIndexList = []
sizeOfPalindromStr = 0
for i in xrange(1, len(str) - 1):
if str[i + 1] == mystack.peek():
# MATCH, Palindrom starts
if sizeOfPalindromStr == 0:
PalindromStartIndexList.append(i)
mystack.pop()
sizeOfPalindromStr += 1
else:
if len(PalindromStartIndexList) != 0:
mymap[PalindromStartIndexList.pop()] = (sizeOfPalindromStr - 1)
sizeOfPalindromStr = 0
mystack.push(str[i])
# get max from mymap accordig to size
IndexForLargestPalindrom = max(mymap, key=mymap.get)
SizeOfLargestPalindrom = mymap[IndexForLargestPalindrom]
# Build largest palindrom string using index and size
LargestPalindromStr = ""
PartPalindromStr = ""
for i in xrange(IndexForLargestPalindrom + 1,
IndexForLargestPalindrom + 1 + SizeOfLargestPalindrom):
PartPalindromStr += str[i]
LargestPalindromStr = PartPalindromStr[::-1] + str[
IndexForLargestPalindrom] + PartPalindromStr
print LargestPalindromStr