perf: move to interned string and construct the graph with usize

Author: anastygnome

Cargo.lock

@@ -1,7 +1,7 @@
 # coreutils (uutils)
 # * see the repository LICENSE, README, and CONTRIBUTING files for more information
 
-# spell-checker:ignore (libs) bigdecimal datetime serde bincode gethostid kqueue libselinux mangen memmap uuhelp startswith constness expl unnested logind cfgs
+# spell-checker:ignore (libs) bigdecimal datetime serde bincode gethostid kqueue libselinux mangen memmap uuhelp startswith constness expl unnested logind cfgs indexmap
 
 [package]
 name = "coreutils"
@@ -374,6 +374,7 @@ time = { version = "0.3.36" }
 unicode-width = "0.2.0"
 unit-prefix = "0.5"
 utmp-classic = "0.1.6"
+indexmap = '2.12.1'
 uutils_term_grid = "0.7"
 walkdir = "2.5"
 winapi-util = "0.1.8"
@@ -521,6 +522,7 @@ who = { optional = true, version = "0.5.0", package = "uu_who", path = "src/uu/w
 whoami = { optional = true, version = "0.5.0", package = "uu_whoami", path = "src/uu/whoami" }
 yes = { optional = true, version = "0.5.0", package = "uu_yes", path = "src/uu/yes" }
 
+
 # this breaks clippy linting with: "tests/by-util/test_factor_benches.rs: No such file or directory (os error 2)"
 # factor_benches = { optional = true, version = "0.0.0", package = "uu_factor_benches", path = "tests/benches/factor" }
 
@@ -543,6 +545,7 @@ sha1 = { workspace = true, features = ["std"] }
 tempfile.workspace = true
 time = { workspace = true, features = ["local-offset"] }
 unindent = "0.2.3"
+indexmap.workspace = true
 uutests.workspace = true
 uucore = { workspace = true, features = [
   "mode",

Cargo.toml

@@ -89,6 +89,8 @@ skip = [
   { name = "itertools", version = "0.13.0" },
   # ordered-multimap
   { name = "hashbrown", version = "0.14.5" },
+  # indexmap
+  { name = "hashbrown", version = "0.16.1" },
   # cexpr (via bindgen)
   { name = "nom", version = "7.1.3" },
   # const-random-macro, rand_core

deny.toml

@@ -1,3 +1,4 @@
+# spell-checker:ignore (libs) indexmap
 [package]
 name = "uu_tsort"
 description = "tsort ~ (uutils) topologically sort input (partially ordered) pairs"
@@ -22,7 +23,7 @@ clap = { workspace = true }
 thiserror = { workspace = true }
 uucore = { workspace = true }
 fluent = { workspace = true }
-
+indexmap = { workspace = true }
 [[bin]]
 name = "tsort"
 path = "src/main.rs"