Two Pointer Recursion — Combine Strategies

Sometimes recursion handles smaller subproblems while each level uses two pointers on a slice (divide & conquer on arrays).

Try this in Python

def is_palindrome_range(s: str, lo: int, hi: int) -> bool:
    while lo < hi:
        if s[lo] != s[hi]:
            return False
        lo += 1
        hi -= 1
    return True


print(is_palindrome_range("racecar", 0, 6))

Key takeaways

• Palindrome check is recursive-friendly base.
• Recursion + two pointers appears in advanced string DP.
• Always define base case on slice length 0/1.