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One Pass

Math​

268. Missing Number​

Easy·
Solutions:
Visualize
class Solution:
def missingNumber(self, nums: List[int]) -> int:
xor = len(nums)
for index in range(len(nums)):
xor = xor ^ index ^ nums[index]
return xor

Running Extremes​

Second Largest​

Easy·
Solutions:
Visualize
class Solution:
def getSecondLargest(self, arr):
first_max, second_max = -1, -1
for i in arr:
if first_max < i:
second_max = first_max
first_max = i
elif first_max > i and second_max < i:
second_max = i
return second_max

1796. Second Largest Digit in a String​

Easy·
Solutions:
Visualize
class Solution:
def secondHighest(self, s: str) -> int:
first_max = second_max = "-"
for i in s:
if not i.isdigit():
continue
if first_max < i:
second_max = first_max
first_max = i
elif first_max > i and second_max < i:
second_max = i
 
# print(first_max, second_max)
return int(second_max) if second_max != "-" else -1

Greedy Scan​

2259. Remove Digit From Number to Maximize Result​

Easy·
Solutions:
Visualize
class Solution:
def removeDigit(self, number: str, digit: str) -> str:
n = len(number)
last_occ = 0
for i in range(n - 1):
if number[i] == digit:
if number[i + 1] > digit:
return number[:i] + number[i + 1 :]
last_occ = i
if number[-1] == digit:
last_occ = n - 1
return number[:last_occ] + number[last_occ + 1 :]