Palindrome Two Pointers

Easy

Python

def is_palindrome(s):
    l,r=0,len(s)-1
    while l<r:
        if s[l]!=s[r]: return False
        l+=1; r-=1
    return True

Java

public boolean isPalindrome(String s){
    int l=0,r=s.length()-1;
    while(l<r){
        if(s.charAt(l)!=s.charAt(r)) return false;
        l++; r--;
    } return true;
}

Key Insight

Direct indexing vs charAt(). True/False vs true/false.

Python → Java Differences

s[l] vs s.charAt(l)
True/False vs true/false
Two-pointer identical

Python

def is_palindrome(s):
    l,r=0,len(s)-1
    while l<r:
        if s[l]!=s[r]: return False
        l+=1; r-=1
    return True

Java

public boolean isPalindrome(String s){
    int l=0,r=s.length()-1;
    while(l<r){
        if(s.charAt(l)!=s.charAt(r)) return false;
        l++; r--;
    } return true;
}

Algorithm Steps

1. Compare from both ends
2. Move inward

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