rename repo, subdir for yearly challenges

2021-07-25 11:17:46 +02:00
parent 1806f79e14
commit 4a2318edc9
203 changed files with 212 additions and 1 deletions
--- a/2020/day19/ex1.bash
+++ b/2020/day19/ex1.bash
@@ -0,0 +1,68 @@
+#!/bin/bash
+#
+# ex1.bash: Advent2020 game, day 19/game 1.
+
+CMD=${0##*/}
+set -o noglob
+shopt -s extglob
+
+declare -a RULE=() MATCH=() STRING=()
+# shellcheck disable=SC2034
+declare var_0
+declare -i res=0
+
+# build a regexp use-able by bash =~ operator.
+# Recursively replace rules, until we get final text values.
+# To avoid running subshell, we must create local variables w/ different
+# names at each recursion level (to avoid "circular name reference" error).
+function buildtree {
+    local -i prof="$1"                            # to allow ≠ local names
+    local -n upname="$2"                          # caller variable name
+    local name="var_$prof"                        # local var name, w/ depth
+    eval "local $name"                            # ... declared here
+    shift 2
+    local args=$* res="" arg t
+
+    for arg in $args; do
+        if [[ -z "${arg/[|ab]}" ]]; then
+            res+="$arg"
+        else
+            if [[ ! -v MATCH[$arg] ]]; then
+                buildtree "$((prof+1))" "$name" "${RULE[$arg]}"
+                t="${!name}"
+                #[[ ! "$t" =~ ^.$ ]] && t="($t)"
+                if [[ ! "$t" =~ ^[ab]+$ ]] && [[ "${t:0:1}${t: -1}" != "()" ]]; then
+                    t="($t)"
+                fi
+                MATCH[$arg]="$t"
+            fi
+            res+=${MATCH[$arg]}
+        fi
+    done
+    # shellcheck disable=SC2034
+    upname="$res"
+}
+
+while read -r line; do
+    case ${line:0:1} in
+        [0-9]*)                                   # rule
+            rule=${line%:*}
+            val=${line#*: }
+            RULE[$rule]="${val//\"}"
+            ;;
+        [a-z]*)                                   # string
+            STRING+=("$line")
+            ;;
+    esac
+done
+
+buildtree 1 var_0 0
+#printf "RULE ZERO = %s\n" "${MATCH[0]}"
+
+for str in "${STRING[@]}"; do
+    [[ "$str" =~ ^${MATCH[0]}$ ]] && ((res++))
+done
+
+printf "%s : res=%d\n" "$CMD" "$res"
+
+exit 0