text: Stores visited segments
code: Set < String > s = new HashSet < > ( ) ; for ( int i = 0 ; i < path . length ( ) ; i ++ ) { int p = x ; int q = y ; if ( path . charAt ( i ) == ' N ' ) y ++ ; else if ( path . charAt ( i ) == ' S ' ) y -- ; else if ( path . charAt ( i ) == ' E ' ) x ++ ; else if ( path . charAt ( i ) == ' W ' ) x -- ;