Sleep - Practice Coding Problems

Sleep - Problem

JavaScript Easy

Given a positive integer millis, write an asynchronous function that sleeps for millis milliseconds. The function can resolve to any value.

Note: Minor deviation from millis in the actual sleep duration is acceptable.

Input & Output

Example 1 — Basic Sleep

$ Input: millis = 1000

› Output: "Sleep completed"

💡 Note: Function sleeps for 1000 milliseconds (1 second) and then resolves with a value

Example 2 — Short Sleep

$ Input: millis = 100

› Output: "Sleep completed"

💡 Note: Function sleeps for 100 milliseconds and resolves quickly

Example 3 — Minimal Sleep

$ Input: millis = 1

› Output: "Sleep completed"

💡 Note: Function sleeps for just 1 millisecond, the minimum valid input

Constraints

1 ≤ millis ≤ 1000

Visualization

Tap to expand

Understanding the Visualization

Input

Positive integer millis (e.g., 1000)

Process

Create async function that waits for millis milliseconds

Output

Promise that resolves after the delay

Key Takeaway

🎯 Key Insight: Wrap setTimeout in a Promise to create awaitable sleep functions

Asked in

G Google 25 M Microsoft 20 f Facebook 15 a Amazon 18

The key insight is wrapping setTimeout in a Promise to make it compatible with async/await. Best approach is Promise-based setTimeout for clean asynchronous code. Time: O(1), Space: O(1)

Common Approaches

Approach	Time	Space	Notes
✓ Callback-based setTimeout	O(1)	O(1)	Use basic setTimeout with callback function
Promise-based setTimeout	O(1)	O(1)	Wrap setTimeout in a Promise for async/await compatibility

Callback-based setTimeout — Algorithm Steps

Use setTimeout with a callback function
Wait for the specified milliseconds
Execute callback when timer expires

Visualization

Tap to expand

Step-by-Step Walkthrough

Setup Timer

setTimeout registers callback for future execution

Wait Period

Timer counts down the specified milliseconds

Execute Callback

Callback function runs when timer expires

Code -

solution.c — C

#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <string.h>

char* solution(int millis) {
    usleep(millis * 1000); // usleep takes microseconds
    return "Done";
}

int main() {
    int millis;
    scanf("%d", &millis);
    char* result = solution(millis);
    printf("\"%s\"\n", result);
    return 0;
}

Time & Space Complexity

Time Complexity

⏱️

O(1)

Single setTimeout call with constant operations

✓ Linear Growth

Space Complexity

O(1)

Only stores timer reference, no additional data structures

✓ Linear Space

12.0K Views

Medium Frequency

~10 min Avg. Time

450 Likes

Ln 1, Col 1

Smart Actions

💡 Explanation

AI Ready

💡 Suggestion Tab to accept Esc to dismiss

// Output will appear here after running code

Code Editor Closed

Click the red button to reopen

Input & Output

Constraints

Visualization

Related Problems

Common Approaches

Callback-based setTimeout — Algorithm Steps

Visualization

Code -

Time & Space Complexity

Select Compiler