Add flags to gcc invocations

.drone.yml

@@ -13,22 +13,15 @@ steps:
     image: python:3.11-rc-alpine
     commands:
       - python3 -c "print(6 * 7)"
-  - name: algo2
+  - name: pairingheap
     image: gcc:12.2.0
     commands:
-      - cd algo2
-      - gcc -o pairingheap pairingheap.c
-      - ./pairingheap
-
----
-kind: pipeline
-type: docker
-name: haskell
-
-steps:
-  - name: radix-heap
-    image: nixos/nix:2.11.0
+      - cd algo2/pairingheap
+      - gcc -Wall -Werror -o main pairingheap.c
+      - ./main
+  - name: radixheap
+    image: gcc:12.2.0
     commands:
-      - cd algo2/radix-heap
-      - stack build
-      - stack test
+      - cd algo2/radixheap
+      - gcc -Wall -Werror -o main radixheap.c
+      - ./main

.gitignore

@@ -1,2 +1,2 @@
 .stack-work
-algo2/pairingheap
+main

algo2/radix-heap/default.nix

@@ -1,20 +0,0 @@
-{
-  pkgs ? import ./nix/nixpkgs.nix {}
-}:
-let
-  ghc = import ./nix/ghc.nix;
-
-  paths =
-    [
-      # Nix tooling
-      pkgs.niv
-      pkgs.nix-tree
-
-      # Haskell tooling
-      pkgs.stack
-      (ghc pkgs)
-    ];
-in
-  pkgs.mkShell {
-    buildInputs = paths;
-  }

algo2/radix-heap/nix/ghc.nix

@@ -1,3 +0,0 @@
-pkgs:
-pkgs.haskellPackages.ghcWithPackages (pkgs: with pkgs; [
-])

algo2/radix-heap/nix/nixpkgs.nix

@@ -1,5 +0,0 @@
-{}:
-let
-  sources = import ./sources.nix;
-in
-  import sources.nixpkgs {}

algo2/radix-heap/nix/sources.json

@@ -1,15 +0,0 @@
-{
-    "nixpkgs": {
-        "branch": "nixpkgs-unstable",
-        "description": "Nix Packages collection",
-        "homepage": null,
-        "owner": "NixOS",
-        "repo": "nixpkgs",
-        "rev": "0343e3415784b2cd9c68924294794f7dbee12ab3",
-        "sha256": "0ypgcim0vbv2742m7rb1010ga4zlayvpdma5qqw13brp8q5vjvcy",
-        "type": "tarball",
-        "url": "https://github.com/NixOS/nixpkgs/archive/0343e3415784b2cd9c68924294794f7dbee12ab3.tar.gz",
-        "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz",
-        "version": "5e7fb7699c84da3420495e40459dfbff459c16e4"
-    }
-}

algo2/radix-heap/nix/sources.nix

@@ -1,174 +0,0 @@
-# This file has been generated by Niv.
-
-let
-
-  #
-  # The fetchers. fetch_<type> fetches specs of type <type>.
-  #
-
-  fetch_file = pkgs: name: spec:
-    let
-      name' = sanitizeName name + "-src";
-    in
-      if spec.builtin or true then
-        builtins_fetchurl { inherit (spec) url sha256; name = name'; }
-      else
-        pkgs.fetchurl { inherit (spec) url sha256; name = name'; };
-
-  fetch_tarball = pkgs: name: spec:
-    let
-      name' = sanitizeName name + "-src";
-    in
-      if spec.builtin or true then
-        builtins_fetchTarball { name = name'; inherit (spec) url sha256; }
-      else
-        pkgs.fetchzip { name = name'; inherit (spec) url sha256; };
-
-  fetch_git = name: spec:
-    let
-      ref =
-        if spec ? ref then spec.ref else
-          if spec ? branch then "refs/heads/${spec.branch}" else
-            if spec ? tag then "refs/tags/${spec.tag}" else
-              abort "In git source '${name}': Please specify `ref`, `tag` or `branch`!";
-    in
-      builtins.fetchGit { url = spec.repo; inherit (spec) rev; inherit ref; };
-
-  fetch_local = spec: spec.path;
-
-  fetch_builtin-tarball = name: throw
-    ''[${name}] The niv type "builtin-tarball" is deprecated. You should instead use `builtin = true`.
-        $ niv modify ${name} -a type=tarball -a builtin=true'';
-
-  fetch_builtin-url = name: throw
-    ''[${name}] The niv type "builtin-url" will soon be deprecated. You should instead use `builtin = true`.
-        $ niv modify ${name} -a type=file -a builtin=true'';
-
-  #
-  # Various helpers
-  #
-
-  # https://github.com/NixOS/nixpkgs/pull/83241/files#diff-c6f540a4f3bfa4b0e8b6bafd4cd54e8bR695
-  sanitizeName = name:
-    (
-      concatMapStrings (s: if builtins.isList s then "-" else s)
-        (
-          builtins.split "[^[:alnum:]+._?=-]+"
-            ((x: builtins.elemAt (builtins.match "\\.*(.*)" x) 0) name)
-        )
-    );
-
-  # The set of packages used when specs are fetched using non-builtins.
-  mkPkgs = sources: system:
-    let
-      sourcesNixpkgs =
-        import (builtins_fetchTarball { inherit (sources.nixpkgs) url sha256; }) { inherit system; };
-      hasNixpkgsPath = builtins.any (x: x.prefix == "nixpkgs") builtins.nixPath;
-      hasThisAsNixpkgsPath = <nixpkgs> == ./.;
-    in
-      if builtins.hasAttr "nixpkgs" sources
-      then sourcesNixpkgs
-      else if hasNixpkgsPath && ! hasThisAsNixpkgsPath then
-        import <nixpkgs> {}
-      else
-        abort
-          ''
-            Please specify either <nixpkgs> (through -I or NIX_PATH=nixpkgs=...) or
-            add a package called "nixpkgs" to your sources.json.
-          '';
-
-  # The actual fetching function.
-  fetch = pkgs: name: spec:
-
-    if ! builtins.hasAttr "type" spec then
-      abort "ERROR: niv spec ${name} does not have a 'type' attribute"
-    else if spec.type == "file" then fetch_file pkgs name spec
-    else if spec.type == "tarball" then fetch_tarball pkgs name spec
-    else if spec.type == "git" then fetch_git name spec
-    else if spec.type == "local" then fetch_local spec
-    else if spec.type == "builtin-tarball" then fetch_builtin-tarball name
-    else if spec.type == "builtin-url" then fetch_builtin-url name
-    else
-      abort "ERROR: niv spec ${name} has unknown type ${builtins.toJSON spec.type}";
-
-  # If the environment variable NIV_OVERRIDE_${name} is set, then use
-  # the path directly as opposed to the fetched source.
-  replace = name: drv:
-    let
-      saneName = stringAsChars (c: if isNull (builtins.match "[a-zA-Z0-9]" c) then "_" else c) name;
-      ersatz = builtins.getEnv "NIV_OVERRIDE_${saneName}";
-    in
-      if ersatz == "" then drv else
-        # this turns the string into an actual Nix path (for both absolute and
-        # relative paths)
-        if builtins.substring 0 1 ersatz == "/" then /. + ersatz else /. + builtins.getEnv "PWD" + "/${ersatz}";
-
-  # Ports of functions for older nix versions
-
-  # a Nix version of mapAttrs if the built-in doesn't exist
-  mapAttrs = builtins.mapAttrs or (
-    f: set: with builtins;
-    listToAttrs (map (attr: { name = attr; value = f attr set.${attr}; }) (attrNames set))
-  );
-
-  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/lists.nix#L295
-  range = first: last: if first > last then [] else builtins.genList (n: first + n) (last - first + 1);
-
-  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L257
-  stringToCharacters = s: map (p: builtins.substring p 1 s) (range 0 (builtins.stringLength s - 1));
-
-  # https://github.com/NixOS/nixpkgs/blob/0258808f5744ca980b9a1f24fe0b1e6f0fecee9c/lib/strings.nix#L269
-  stringAsChars = f: s: concatStrings (map f (stringToCharacters s));
-  concatMapStrings = f: list: concatStrings (map f list);
-  concatStrings = builtins.concatStringsSep "";
-
-  # https://github.com/NixOS/nixpkgs/blob/8a9f58a375c401b96da862d969f66429def1d118/lib/attrsets.nix#L331
-  optionalAttrs = cond: as: if cond then as else {};
-
-  # fetchTarball version that is compatible between all the versions of Nix
-  builtins_fetchTarball = { url, name ? null, sha256 }@attrs:
-    let
-      inherit (builtins) lessThan nixVersion fetchTarball;
-    in
-      if lessThan nixVersion "1.12" then
-        fetchTarball ({ inherit url; } // (optionalAttrs (!isNull name) { inherit name; }))
-      else
-        fetchTarball attrs;
-
-  # fetchurl version that is compatible between all the versions of Nix
-  builtins_fetchurl = { url, name ? null, sha256 }@attrs:
-    let
-      inherit (builtins) lessThan nixVersion fetchurl;
-    in
-      if lessThan nixVersion "1.12" then
-        fetchurl ({ inherit url; } // (optionalAttrs (!isNull name) { inherit name; }))
-      else
-        fetchurl attrs;
-
-  # Create the final "sources" from the config
-  mkSources = config:
-    mapAttrs (
-      name: spec:
-        if builtins.hasAttr "outPath" spec
-        then abort
-          "The values in sources.json should not have an 'outPath' attribute"
-        else
-          spec // { outPath = replace name (fetch config.pkgs name spec); }
-    ) config.sources;
-
-  # The "config" used by the fetchers
-  mkConfig =
-    { sourcesFile ? if builtins.pathExists ./sources.json then ./sources.json else null
-    , sources ? if isNull sourcesFile then {} else builtins.fromJSON (builtins.readFile sourcesFile)
-    , system ? builtins.currentSystem
-    , pkgs ? mkPkgs sources system
-    }: rec {
-      # The sources, i.e. the attribute set of spec name to spec
-      inherit sources;
-
-      # The "pkgs" (evaluated nixpkgs) to use for e.g. non-builtin fetchers
-      inherit pkgs;
-    };
-
-in
-mkSources (mkConfig {}) // { __functor = _: settings: mkSources (mkConfig settings); }

algo2/radix-heap/radix-heap.cabal

@@ -1,25 +0,0 @@
-name:                radix-heap
-version:             0.1
-synopsis:            Radix heap implementation.
-description:         Radix heap implementation.
-homepage:            
-license:             MIT
-author:              Paul Brinkmeier <hallo@pbrinkmeier.de>
-build-type:          Simple
-cabal-version:       >=1.10
-
-library
-  hs-source-dirs:      src
-  exposed-modules:     Data.RadixHeap
-
-  build-depends:       base
-  ghc-options:         -Wall -Wextra
-  default-language:    Haskell2010
-
-test-suite test-suite
-  type:                exitcode-stdio-1.0
-  main-is:             Main.hs
-  hs-source-dirs:      tests
-  ghc-options:         -Wall -Wextra
-  build-depends:       base >= 4.7 && < 5
-  default-language:    Haskell2010

algo2/radix-heap/src/Data/RadixHeap.hs

@@ -1,3 +0,0 @@
-module Data.RadixHeap where
-
-data RadixHeap

algo2/radix-heap/stack-shell.nix

@@ -1,12 +0,0 @@
-{}:
-let
-  pkgs = import ./nix/nixpkgs.nix {};
-  ghc = import ./nix/ghc.nix;
-in
-  pkgs.haskell.lib.buildStackProject {
-    name = "radix-heap";
-    ghc = ghc pkgs;
-    buildInputs = with pkgs; [
-      zlib
-    ];
-  }

algo2/radix-heap/stack.yaml

@@ -1,8 +0,0 @@
-resolver: ghc-9.0.2
-packages:
-- .
-
-nix:
-  enable: true
-  shell-file: stack-shell.nix
-  path: ["nixpkgs=./nix/nixpkgs.nix"]

algo2/radix-heap/tests/Main.hs

@@ -1,4 +0,0 @@
-module Main where
-
-main :: IO ()
-main = putStrLn "All tests passed."

algo2/radixheap/radixheap.c

@@ -0,0 +1,191 @@
+#include <assert.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+struct RHeapNode {
+    struct RHeapNode *left;
+    struct RHeapNode *right;
+    unsigned int key;
+};
+
+// insert a node at the end of a list (left of the head)
+// Before:
+// ┌─┐  ┌────┐  ┌─┐    ┌─┐
+// │l◄──►list◄──►r│  ◄─┤h├─►
+// └─┘  └────┘  └─┘    └─┘
+//  After:
+// ┌─┐  ┌─┐  ┌────┐  ┌─┐
+// │l◄──►h◄──►list◄──►r│
+// └─┘  └─┘  └────┘  └─┘
+void rhn_insert(struct RHeapNode *list, struct RHeapNode *h) {
+    assert(h->left == NULL);
+    assert(h->right == NULL);
+
+    list->left->right = h;
+    h->left = list->left;
+    h->right = list;
+    list->left = h;
+}
+
+// remove a node from its list
+// Before:
+// ┌─┐  ┌─┐  ┌─┐
+// │l◄──►h◄──►r│
+// └─┘  └─┘  └─┘
+// After:
+// ┌─┐  ┌─┐    ┌─┐
+// │l◄──►r│  ◄─┤h├─►
+// └─┘  └─┘    └─┘
+void rhn_remove(struct RHeapNode *h) {
+    h->left->right = h->right;
+    h->right->left = h->left;
+
+    h->left = NULL;
+    h->right = NULL;
+}
+
+struct RHeap {
+    // last deleted element, initially 0
+    unsigned int min;
+    size_t buckets_size;
+    struct RHeapNode *buckets;
+};
+
+static unsigned int uintlog2(unsigned int x) {
+    return 8 * sizeof(unsigned int) - __builtin_clz(x);
+}
+
+void rh_init(struct RHeap *rh, unsigned int c) {
+    unsigned int k = 1 + uintlog2(c);
+
+    rh->min = 0;
+    rh->buckets_size = 1 + k; // extra space for bucket -1
+    rh->buckets = malloc(rh->buckets_size * sizeof(struct RHeapNode));
+    for (size_t i = 0; i < rh->buckets_size; i++) {
+        rh->buckets[i].left = &rh->buckets[i];
+        rh->buckets[i].right = &rh->buckets[i];
+    }
+}
+
+void rh_free(struct RHeap *rh) {
+    free(rh->buckets);
+}
+
+static int msd(unsigned int x, unsigned int y) {
+    return 8 * sizeof(unsigned int) - __builtin_clz(x ^ y) - 1;
+}
+
+static size_t min(size_t x, size_t y) {
+    return x <= y ? x : y;
+}
+
+void rh_insert(struct RHeap *rh, struct RHeapNode *h) {
+    size_t bucket =
+        h->key == rh->min
+        ? 0
+        : min(1 + msd(h->key, rh->min), rh->buckets_size - 1);
+
+    rhn_insert(&rh->buckets[bucket], h);
+}
+
+struct RHeapNode *rh_insert_malloc(struct RHeap *rh, unsigned int key) {
+    struct RHeapNode *h = malloc(sizeof(struct RHeapNode));
+    h->left = NULL;
+    h->right = NULL;
+    h->key = key;
+
+    rh_insert(rh, h);
+
+    return h;
+}
+
+void rh_print(struct RHeap *rh) {
+    printf("d* = %u\n", rh->min);
+    for (size_t i = 0; i < rh->buckets_size; i++) {
+        printf("B[%3zd]:", (ssize_t) i - 1);
+
+        struct RHeapNode *curr = rh->buckets[i].right;
+        while (curr != &rh->buckets[i]) {
+            printf(" %u", curr->key);
+            curr = curr->right;
+        }
+
+        printf("\n");
+    }
+}
+
+struct RHeapNode *rh_deletemin(struct RHeap *rh) {
+    // if bucket -1 is empty
+    if (rh->buckets[0].right == &rh->buckets[0]) {
+        assert(rh->buckets[0].left == &rh->buckets[0]);
+
+        // find first non-empty bucket B[i]
+        size_t i = 1;
+        for (; rh->buckets[i].right == &rh->buckets[i]; i++) {
+            assert(i < rh->buckets_size);
+        }
+
+        struct RHeapNode *bucket = &rh->buckets[i];
+        // find smallest element in B
+        struct RHeapNode *minb = bucket->right;
+        
+        for (struct RHeapNode *curr = minb->right; curr != bucket; curr = curr->right) {
+            if (curr->key < minb->key) {
+                minb = curr;
+            }
+        }
+        assert(minb != bucket);
+
+        // update d* and move min(B[i]) to bucket -1
+        rh->min = minb->key;
+        rhn_remove(minb);
+        rhn_insert(&rh->buckets[0], minb);
+
+        // move remaining elements of B[i] to bucket -1
+        while (bucket->right != bucket) {
+            struct RHeapNode *tmp = bucket->right;
+            rhn_remove(bucket->right);
+            rh_insert(rh, tmp);
+        }
+    }
+
+    assert(rh->buckets[0].right != &rh->buckets[0]);
+    struct RHeapNode *minnode = rh->buckets[0].right;
+    rhn_remove(minnode);
+
+    return minnode;
+}
+
+static void insert_and_print(struct RHeap *rh, unsigned int key) {
+    rh_insert_malloc(rh, key);
+    printf("# After insert(%u):\n", key);
+    rh_print(rh);
+}
+
+static void deletemin_and_print(struct RHeap *rh) {
+    struct RHeapNode *h = rh_deletemin(rh);
+    printf("# After deleteMin() == %u:\n", h->key);
+    rh_print(rh);
+    free(h);
+}
+
+int main() {
+    struct RHeap rh;
+    rh_init(&rh, 6);
+
+    rh_insert_malloc(&rh, 5);
+    struct RHeapNode *h = rh_deletemin(&rh);
+    free(h);
+    rh_print(&rh);
+
+    insert_and_print(&rh, 6);
+    insert_and_print(&rh, 10);
+    insert_and_print(&rh, 7);
+    deletemin_and_print(&rh);
+    deletemin_and_print(&rh);
+    insert_and_print(&rh, 12);
+    deletemin_and_print(&rh);
+    insert_and_print(&rh, 16);
+
+    rh_free(&rh);
+}