Pattern: sliding window (Variable window)

Sliding window of variable size that satisfy given constraint, i.e Finding continuous substring/subarray that satisfies the given condition. e.g. Longest substring without repeating characters class Solution { public int lengthOfLongestSubstring ( String s ) { int l = 0 ; int r = 0 ; int size = 0 ; int arr [] = new int [ 256 ]; Arrays . fill ( arr ,- 1 ); //intially indices of all the characters are -1 while ( r s . length ()){ char c = s . charAt ( r ); if ( arr [ c ]!=- 1 ){ //seen in the past