def _k_smallest(input_list, k):
"""
O(n*logn) algorithm for finding the first k elemenst
:param input_list:
:return:
"""
sorted_list = MergeSort.merge_sort(input_list)
for i in range(k):
print(sorted_list[i])
return
def remove_duplicates(input_list):
temp = []
sorted_list = MergeSort.merge_sort(input_list)
temp.append(input_list[0])
for i in range(1, len(sorted_list)):
if sorted_list[i] == sorted_list[i - 1]:
continue
else:
temp.append(sorted_list[i])
return temp
def delete_duplicates(input_list):
sorted_list = MergeSort.merge_sort(input_list)
i = 0
while i < len(sorted_list) - 1:
if sorted_list[i] == sorted_list[i + 1]:
sorted_list[i], sorted_list[len(sorted_list) -
1] = sorted_list[len(sorted_list) -
1], sorted_list[i]
del sorted_list[len(sorted_list) - 1]
i += 1
return sorted_list
def check_duplicates_opt(input_list):
"""
O(n*log(n)) algorithm - Sort the list
:param input_list:
:return:
"""
sorted_list = MergeSort.merge_sort(input_list)
for i in range(len(sorted_list)-1):
if sorted_list[i] == sorted_list[i+1]:
return True
return False
def find_numbers(input_list, k):
"""
O(n^2) algorithm
:param input_list:
:return:
"""
sorted_list = MergeSort.merge_sort(input_list)
a = b = 0
pairs_list = []
for i in range(len(input_list)):
a, b = ConstantSum._find_numers_opt(input_list, k - input_list[i])
pairs_list.append((a, b, input_list[i]))
return pairs_list
def _find_number(input_list, k):
sorted_list = MergeSort.merge_sort(input_list)
left = 0
right = len(input_list) - 1
for i in range(len(sorted_list) - 2):
left = i + 1
right = len(input_list) - 1
while left < right:
if input_list[left] + input_list[right] + input_list[i] == k:
return input_list[i], input_list[left], input_list[right]
if input_list[left] + input_list[right] + input_list[i] > k:
right -= 1
elif input_list[left] + input_list[right] + input_list[i] < k:
left += 1
def max_occurance_opt(input_list):
"""
O(n*log(n)) algorithm
:param input_list:
:return:
"""
sorted_list = MergeSort.merge_sort(input_list)
max_idx = 0
count = 1
max_count = 0
for i in range(len(sorted_list) - 1):
if sorted_list[i] == sorted_list[i + 1]:
count += 1
else:
count = 1
if max_count < count:
max_count = count
max_idx = i
return max_count, sorted_list[max_idx]
def _find_majority(input_list):
"""
O(n*log(n)) algorithm
:param input_list:
:return:
"""
sorted_list = MergeSort.merge_sort(input_list)
max_count = 0
count = 0
maxcount_element_idx = 0
for i in range(len(sorted_list) - 1):
if input_list[i] == input_list[i + 1]:
count += 1
else:
count = 1
if max_count < count:
max_count = count
maxcount_element_idx = i
if max_count > len(sorted_list) // 2:
return sorted_list[maxcount_element_idx]
else:
return -1
def _find_numbers(input_list):
"""
O(n*(log(n)) algorithm - Sort the input
:param input_list:
:return:
"""
sorted_list = MergeSort.merge_sort(input_list)
start_idx = 0
end_idx = len(input_list) - 1
min_sum = sys.maxsize
min_left = 0
min_right = len(input_list) - 1
while start_idx < end_idx:
current_sum = input_list[start_idx] + input_list[end_idx]
if abs(current_sum) < abs(min_sum):
min_sum = current_sum
min_left = start_idx
min_right = end_idx
if current_sum < 0:
start_idx += 1
if current_sum > 0:
end_idx -= 1
return input_list[min_left], input_list[min_right]