(0) $ ./tdriver big[1-6].txt | cksum
tdriver (fixed string length=6) start
use std::map
big1.txt: nlines=3515200 ( 0.700 seconds)
big2.txt: nlines=3515200 ( 0.640 seconds)
big3.txt: nlines=3515200 ( 0.711 seconds)
big4.txt: nlines=3515200 ( 0.774 seconds)
big5.txt: nlines=3515200 ( 0.837 seconds)
big6.txt: nlines=3515200 ( 0.901 seconds)
duration:                ( 9.409 seconds)
3181500212 183490425

(1) $ ./tdriver big[1-6].txt | cksum
tdriver (fixed string length=6) start
use std::unordered_map
big1.txt: nlines=3515200 ( 0.986 seconds)
big2.txt: nlines=3515200 ( 1.224 seconds)
big3.txt: nlines=3515200 ( 0.844 seconds)
big4.txt: nlines=3515200 ( 1.724 seconds)
big5.txt: nlines=3515200 ( 0.824 seconds)
big6.txt: nlines=3515200 ( 0.889 seconds)
duration:                (14.335 seconds)
3181500212 183490425

(2) $ ./tdriver big[1-6].txt | cksum
tdriver (fixed string length=6) start
use phmap::flat_hash_map                     w/ absl::Hash
big1.txt: nlines=3515200 ( 0.307 seconds)  ( 0.300 seconds)
big2.txt: nlines=3515200 ( 0.419 seconds)  ( 0.415 seconds)
big3.txt: nlines=3515200 ( 0.529 seconds)  ( 0.517 seconds)
big4.txt: nlines=3515200 ( 0.461 seconds)  ( 0.465 seconds)
big5.txt: nlines=3515200 ( 0.662 seconds)  ( 0.632 seconds)
big6.txt: nlines=3515200 ( 0.506 seconds)  ( 0.508 seconds)
duration:                ( 6.624 seconds)  ( 6.501 seconds)
3181500212 183490425

(3) $ ./tdriver big[1-6].txt | cksum
tdriver (fixed string length=6) start
use phmap::parallel_flat_hash_map            w/ absl::Hash
big1.txt: nlines=3515200 ( 0.370 seconds)  ( 0.363 seconds)
big2.txt: nlines=3515200 ( 0.511 seconds)  ( 0.504 seconds)
big3.txt: nlines=3515200 ( 0.645 seconds)  ( 0.629 seconds)
big4.txt: nlines=3515200 ( 0.597 seconds)  ( 0.557 seconds)
big5.txt: nlines=3515200 ( 0.813 seconds)  ( 0.773 seconds)
big6.txt: nlines=3515200 ( 0.604 seconds)  ( 0.602 seconds)
duration:                ( 7.221 seconds)  ( 7.079 seconds)
3181500212 183490425

(4) $ ./tdriver big[1-6].txt | cksum
tdriver (fixed string length=6) start
use boost::unordered_map
big1.txt: nlines=3515200 ( 0.839 seconds)
big2.txt: nlines=3515200 ( 1.012 seconds)
big3.txt: nlines=3515200 ( 1.280 seconds)
big4.txt: nlines=3515200 ( 0.809 seconds)
big5.txt: nlines=3515200 ( 1.885 seconds)
big6.txt: nlines=3515200 ( 0.763 seconds)
duration:                (13.989 seconds)
3181500212 183490425

(5) $ ./tdriver big[1-6].txt | cksum
tdriver (fixed string length=6) start
use absl::flat_hash_map
use absl::Hash function object in ctor or string view
big1.txt: nlines=3515200 ( 0.383 seconds)
big2.txt: nlines=3515200 ( 0.480 seconds)
big3.txt: nlines=3515200 ( 0.594 seconds)
big4.txt: nlines=3515200 ( 0.502 seconds)
big5.txt: nlines=3515200 ( 0.762 seconds)
big6.txt: nlines=3515200 ( 0.548 seconds)
duration:                ( 7.069 seconds)
3181500212 183490425

(6) $ ./tdriver big[1-6].txt | cksum
tdriver (fixed string length=6) start
use absl::node_hash_map
use absl::Hash function object in ctor or string view
big1.txt: nlines=3515200 ( 0.531 seconds)
big2.txt: nlines=3515200 ( 0.687 seconds)
big3.txt: nlines=3515200 ( 0.950 seconds)
big4.txt: nlines=3515200 ( 0.597 seconds)
big5.txt: nlines=3515200 ( 1.426 seconds)
big6.txt: nlines=3515200 ( 0.634 seconds)
duration:                (12.332 seconds)
3181500212 183490425

(7) $ ./tdriver big[1-6].txt | cksum
tdriver (fixed string length=6) start
use ankerl::unordered_dense::map             w/ absl::Hash
big1.txt: nlines=3515200 ( 0.480 seconds)  ( 0.388 seconds)
big2.txt: nlines=3515200 ( 0.627 seconds)  ( 0.498 seconds)
big3.txt: nlines=3515200 ( 0.358 seconds)  ( 0.368 seconds)
big4.txt: nlines=3515200 ( 0.969 seconds)  ( 0.689 seconds)
big5.txt: nlines=3515200 ( 0.380 seconds)  ( 0.390 seconds)
big6.txt: nlines=3515200 ( 0.373 seconds)  ( 0.379 seconds)
duration:                ( 6.121 seconds)  ( 5.795 seconds)
3181500212 183490425