rename repo, subdir for yearly challenges

2020/day10/ex1.bash

@@ -0,0 +1,31 @@
+#!/bin/bash
+#
+# ex1.bash: Advent2020 game, day 10/game 1.
+
+CMD=${0##*/}
+shopt -s extglob
+
+declare -a numbers
+readarray -t numbers <<< "$(sort -n)"
+numbers=(0 "${numbers[@]}")
+size=${#numbers[@]}
+((last=${numbers[size-1]}+3))
+numbers+=("$last")
+((size++))
+#echo S="$size" $last "[${numbers[@]}]"
+
+# last
+declare -a res=(0 0 0 0)
+
+for ((i=1; i<size; ++i)); do
+	prev=${numbers[$i-1]}
+	cur=${numbers[$i]}
+	diff=$((cur-prev))
+	((res[diff]++))
+done
+res1="${res[1]}"
+res3="${res[3]}"
+
+printf "%s : diff1=%d diff2=%d res=%d\n" "$CMD" "$res1" "$res3" $((res1*res3))
+
+exit 0