Tutorialspoint
Problem
Solution
Submissions
Back

Check if String Contains Substring

Certification: Basic Level Accuracy: 0% Submissions: 0 Points: 5

Write a JavaScript program to check if a given string contains a specific substring. The function should return true if the substring is found within the main string, and false otherwise. The search should be case-sensitive, and you should implement this without using the built-in includes() method or indexOf() method.

Example 1
    
  
  • Input: mainString = "Hello World Programming", substring = "World"
    • 
  
  • Output: true
    • 
  
  • Explanation: 
    • Start searching from index 0 of the main string. 
    • Compare characters: H≠W, e≠W, l≠W, l≠W, o≠W, space≠W. 
    • At index 6, find 'W' which matches the first character of "World". 
    • Continue matching: W=W, o=o, r=r, l=l, d=d - all characters match. 
    • Complete substring "World" found at index 6, return true.
    •
Example 2
    
  
  • Input: mainString = "JavaScript is awesome", substring = "Python"
    • 
  
  • Output: false
    • 
  
  • Explanation: 
    • Search through the entire main string for "Python". 
    • Check each possible starting position but no complete match found. 
    • 'P' character is not present anywhere in "JavaScript is awesome". 
    • Since no starting character matches, the substring is not present. 
    • Return false as "Python" is not found in the main string.
    •
Constraints
    
  
  • 1 ≤ mainString.length ≤ 1000
    • 
  
  • 1 ≤ substring.length ≤ 100
    • 
  
  • Both strings contain only ASCII characters
    • 
  
  • Search is case-sensitive
    • 
  
  • Time Complexity: O(n*m) where n is main string length and m is substring length
    • 
  
  • Space Complexity: O(1)
    •
StringsControl StructuresGoldman SachsSwiggy
Editorial

Login to view the detailed solution and explanation for this problem.

My Submissions
All Solutions
Refresh
Lang Status Date Code
You do not have any submissions for this problem.
Refresh
User Lang Status Date Code
No submissions found.

Please Login to continue
Solve Problems

 
 
 
Output Window
Clear All Apply Filters

Trending

Others

SIGN IN

Don't have an account? Register

Hint
Solution

Solution Hints

    
  
  • Use nested loops to check every possible starting position in the main string
    • 
  
  • For each starting position, compare characters of substring with main string
    • 
  
  • If all characters match consecutively, return true
    • 
  
  • If any character doesn't match, move to the next starting position
    • 
  
  • Check boundary conditions to avoid index out of bounds errors
    • 
  
  • If no complete match is found after checking all positions, return false
    • 
  
  • Handle edge case where substring is longer than main string
    •

Steps to solve by this approach:

 Step 1: Handle edge cases by checking if substring is longer than main string or if substring is empty
 Step 2: Use an outer loop to iterate through each possible starting position in the main string
 Step 3: Limit the outer loop to avoid checking positions where substring cannot fit completely
 Step 4: For each starting position, use an inner loop to compare substring characters with main string characters
 Step 5: Set a boolean flag to track if all characters match at the current position
 Step 6: If any character doesn't match, break the inner loop and set the match flag to false
 Step 7: If all characters match (match flag remains true), return true immediately

Submitted Code :