Represents first and last numbers of each type ( modulo 0 and 1 )
int L [ 2 ] = { 0 } , R [ 2 ] = { 0 } ; L [ l % 2 ] = l , R [ r % 2 ] = r ; l ++ , r -- ; if ( l <= tR && r >= tL ) L [ l % 2 ] = l , R [ r % 2 ] = r ;