Lexicographically Smallest

Table of Contents

• 402. Remove K Digits (Medium)
• 1673. Find the Most Competitive Subsequence (Medium)
• 316. Remove Duplicate Letters (Medium)
• 1081. Smallest Subsequence of Distinct Characters (Medium)
• 321. Create Maximum Number (Hard)
• 2030. Smallest K-Length Subsequence With Occurrences of a Letter (Hard)

402. Remove K Digits

• LeetCode | LeetCode CH (Medium)

• Tags: string, stack, greedy, monotonic stack

1673. Find the Most Competitive Subsequence

• LeetCode | LeetCode CH (Medium)

• Tags: array, stack, greedy, monotonic stack

316. Remove Duplicate Letters

• LeetCode | LeetCode CH (Medium)

• Tags: string, stack, greedy, monotonic stack

316. Remove Duplicate Letters - Python Solution

# Monotonic Stack
def removeDuplicateLetters(s: str) -> str:
    stack = []
    seen = set()
    last = {c: i for i, c in enumerate(s)}

    for i, c in enumerate(s):
        if c not in seen:
            while stack and c < stack[-1] and i < last[stack[-1]]:
                seen.discard(stack.pop())
            seen.add(c)
            stack.append(c)

    return "".join(stack)


s = "cbacdcbc"
print(removeDuplicateLetters(s))  # acdb

1081. Smallest Subsequence of Distinct Characters

• LeetCode | LeetCode CH (Medium)

• Tags: string, stack, greedy, monotonic stack

321. Create Maximum Number

• LeetCode | LeetCode CH (Hard)

• Tags: array, two pointers, stack, greedy, monotonic stack

2030. Smallest K-Length Subsequence With Occurrences of a Letter

• LeetCode | LeetCode CH (Hard)

• Tags: string, stack, greedy, monotonic stack

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