Benchmark: timing 2500 iterations of grepGen, mapGen, smartGen...
   grepGen: 34 wallclock secs (34.35 usr +  0.00 sys = 34.35 CPU) @ 72.78/s (n=2500)
    mapGen: 14 wallclock secs (14.09 usr +  0.00 sys = 14.09 CPU) @ 177.47/s (n=2500)
  smartGen:  1 wallclock secs ( 0.95 usr +  0.00 sys =  0.95 CPU) @ 2628.81/s (n=2500)
           Rate  grepGen   mapGen smartGen
grepGen  72.8/s       --     -59%     -97%
mapGen    177/s     144%       --     -93%
smartGen 2629/s    3512%    1381%       --
loop counts - grep: 805000, map: 805000, smart: 495000
array sizes - num: 1000000; grep: 100; map: 100; smart: 100
grep:
1 12 15 18 19 20 21 22 23 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 104 105 106 107 108 109 110 111 112 113 114 116 117 118 119
map:
1 12 15 18 19 20 21 22 23 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 104 105 106 107 108 109 110 111 112 113 114 116 117 118 119
smart:
0 1 2 3 5 7 8 9 12 13 15 16 18 19 21 22 23 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 42 43 44 45 46 47 48 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 68 69 70 71 72 73 74 75 76 77 78 79 81 83 84 85 86 87 89 90 91 92 93 94 95 96 97 98 100 101 102 104 105 106 107 108 109 110 111 112 113 116 117 118 119