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How to Solve Minimum Time to Activate String Problem
Master the Minimum Time to Activate String LeetCode problem with undetectable real-time assistance. Get instant solutions and explanations during your coding interviews.
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Start Free for WindowsMedium#3639
LeetCode ProblemMinimum Time to Activate String
You are given a string s of length n and an integer array order, where order is a permutation of the numbers in the range [0, n - 1]. Starting from time t = 0, replace the character at index order[t] in s with '*' at each time step. A substring is valid if it contains at least one '*'. A string is active if the total number of valid substrings is greater than or equal to k. Return the minimum time t at which the string s becomes active. If it is impossible, return -1.
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Problem Breakdown
Understanding the Minimum Time to Activate String Problem
Let's break down this LeetCode problem and understand what makes it challenging in interview settings.
Problem Statement
You are given a string s of length n and an integer array order, where order is a permutation of the numbers in the range [0, n - 1]. Starting from time t = 0, replace the character at index order[t] in s with '*' at each time step. A substring is valid if it contains at least one '*'. A string is active if the total number of valid substrings is greater than or equal to k. Return the minimum time t at which the string s becomes active. If it is impossible, return -1.
MediumProblem #3639
LeetCodeMinimum Time to Activate String
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How Phantom Code Helps
Get real-time assistance for Minimum Time to Activate String problems during coding interviews. Phantom Code provides instant solutions and explanations.
Examples
# Example 1
Input
s = "abc", order = [1,0,2], k = 2
Output
0
# Example 2
Input
s = "cat", order = [0,2,1], k = 6
Output
2
# Example 3
Input
s = "xy", order = [0,1], k = 4
Output
-1
Constraints
1 <= n == s.length <= 105
order.length == n
0 <= order[i] <= n - 1
s consists of lowercase English letters.
order is a permutation of integers from 0 to n - 1.
1 <= k <= 109
How Phantom Code Helps with LeetCode Problems
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Solve Minimum Time to Activate String — You are given a string s of length n and an integer array order, where order is ...
Here's the optimal approach using the right algorithm:
def solve(input):
# Optimal O(n) solution
return result
Time: O(n) | Space: O(n)
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Google Meet
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HackerRank
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Undetectability and technical details
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Frequently Asked Questions
Common questions about solving Minimum Time to Activate String and using Phantom Code during coding interviews.
How does Phantom Code help me solve coding problems like Minimum Time to Activate String during interviews?
Phantom Code generates complete solutions instantly with proper complexity analysis, letting you focus on explaining your approach and demonstrating problem-solving skills rather than getting stuck on implementation details during high-pressure situations.
What if the interviewer asks follow-up questions or modifications to problems like Minimum Time to Activate String?
Phantom Code adapts in real-time. Screenshot the modified problem or use audio mode to capture the interviewer's follow-up, and get an updated solution within seconds — including edge cases and optimizations.
Can Phantom Code help me communicate my solution for problems like Minimum Time to Activate String?
Yes. Phantom Code provides step-by-step approach explanations with 3 progressive thoughts, so you can walk through your solution naturally. It also provides time and space complexity analysis to discuss trade-offs.
How does Phantom Code assist with different programming languages for Minimum Time to Activate String type problems?
Phantom Code supports 11 programming languages including Python, Java, C++, JavaScript, TypeScript, Go, Rust, Ruby, Swift, Kotlin, and C#. Set your preferred language and get idiomatic solutions.
What coding mistakes does Phantom Code help me avoid during Minimum Time to Activate String interviews?
Phantom Code catches common mistakes like off-by-one errors, missing edge cases, incorrect base conditions, and suboptimal approaches. It provides clean, well-structured code that handles all edge cases.
Is Phantom Code detectable when solving problems like Minimum Time to Activate String during live interviews?
No. Phantom Code runs as an invisible desktop overlay that doesn't appear in screen shares, recordings, or proctoring software. It works with Zoom, HackerRank, CodeSignal, CoderPad, and all major platforms.
How does Phantom Code help when I'm struggling with Minimum Time to Activate String style questions under pressure?
The AI provides structured guidance: first the approach (what algorithm/data structure to use and why), then the implementation with clean code, and finally complexity analysis. This helps you think clearly even under pressure.
Does Phantom Code work for the coding platforms used in Minimum Time to Activate String interviews?
Yes. Phantom Code works with all major coding platforms including LeetCode, HackerRank, CodeSignal, CoderPad, HackerEarth, and any browser-based coding environment.
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