Fundamentals · Medium · Free
Explain the two-pointer technique with a sorted array example.
FresherFundamentalsData Structures & Algorithms
Two pointers
On sorted array, move left/right based on sum vs target—O(n) after sort.
java
boolean pairSum(int[] a, int target) {
int l = 0, r = a.length - 1;
while (l < r) {
int s = a[l] + a[r];
if (s == target) return true;
if (s < target) l++; else r--;
}
return false;
}Also used for palindrome check, remove duplicates in-place.