#1869

Easy

auto_awesomeString-driven solution strategy

LeetCode Problem Workspace

Longer Contiguous Segments of Ones than Zeros

Determine if the longest segment of 1s in a binary string is strictly longer than the longest segment of 0s.

Problem Statement

Given a binary string s, return true if the longest contiguous segment of 1's is strictly longer than the longest contiguous segment of 0's in the string. Otherwise, return false.

Note that if there are no 0's, the longest contiguous segment of 0's is considered to have a length of 0. Similarly, if there are no 1's, the longest contiguous segment of 1's is also considered to have a length of 0.

Examples

Example 1

Input: s = "1101"

Output: true

The longest contiguous segment of 1s has length 2: "1101" The longest contiguous segment of 0s has length 1: "1101" The segment of 1s is longer, so return true.

Example 2

Input: s = "111000"

Output: false

The longest contiguous segment of 1s has length 3: "111000" The longest contiguous segment of 0s has length 3: "111000" The segment of 1s is not longer, so return false.

Example 3

Input: s = "110100010"

Output: false

The longest contiguous segment of 1s has length 2: "110100010" The longest contiguous segment of 0s has length 3: "110100010" The segment of 1s is not longer, so return false.

Constraints

1 <= s.length <= 100
s[i] is either '0' or '1'.

Solution Approach

Iterate through the string

Loop through the string to identify contiguous segments of 1s and 0s. Keep track of the longest segment found for both 1s and 0s and compare them.

Compare segment lengths

After identifying the longest segments of 1s and 0s, compare their lengths. If the length of 1s is strictly greater, return true; otherwise, return false.

Edge case handling

Ensure the edge cases are handled where there may be no 1s or no 0s in the string. In these cases, treat the non-existing segment as having a length of 0.

Complexity Analysis

Metric	Value
Time	Depends on the final approach
Space	Depends on the final approach

The time complexity depends on the method used for iterating through the string, typically O(n). The space complexity is O(1) as we only need a few variables to keep track of the longest segments.

What Interviewers Usually Probe

Check if the candidate optimizes the loop to avoid unnecessary comparisons.
Evaluate whether the candidate handles edge cases efficiently.
Look for clear and correct logic when comparing the segment lengths.

Common Pitfalls or Variants

Common pitfalls

Failing to handle the case where the string has no 0s or 1s.
Not correctly identifying the longest contiguous segments of 1s and 0s.
Overcomplicating the approach when a simple linear pass would suffice.

Follow-up variants

Consider an approach where the string is processed only once to track segment lengths.
Implement a solution using dynamic programming if multiple substrings must be compared.
Adapt the solution for binary data in large files where the string cannot fit entirely into memory.

FAQ

How do I approach the 'Longer Contiguous Segments of Ones than Zeros' problem?

Start by iterating through the string, tracking the lengths of contiguous 1s and 0s, and then compare the longest segments to return the correct result.

What is the time complexity of solving the 'Longer Contiguous Segments of Ones than Zeros' problem?

The time complexity is typically O(n), where n is the length of the string, as you need to iterate through the string to identify the segments.

What should I do if there are no 1s or 0s in the string?

If there are no 1s, treat the longest segment of 1s as having length 0. Similarly, treat the longest segment of 0s as having length 0 if there are no 0s.

Can the 'Longer Contiguous Segments of Ones than Zeros' problem be solved without looping through the string?

It is possible to avoid explicit loops in some cases, but typically, a loop is the most straightforward way to identify contiguous segments in a binary string.

How can GhostInterview assist me with this problem?

GhostInterview provides targeted hints, solution strategies, and common pitfalls to ensure you correctly identify and compare contiguous segments in a binary string.

terminal

Solution

Solution 1: Two Passes

We design a function $f(x)$, which represents the length of the longest consecutive substring in string $s$ composed of $x$. If $f(1) > f(0)$, then return `true`, otherwise return `false`.

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class Solution:
    def checkZeroOnes(self, s: str) -> bool:
        def f(x: str) -> int:
            cnt = mx = 0
            for c in s:
                if c == x:
                    cnt += 1
                    mx = max(mx, cnt)
                else:
                    cnt = 0
            return mx

        return f("1") > f("0")

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