66 lines
1.1 KiB
Bash
66 lines
1.1 KiB
Bash
#!/bin/bash
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#
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# ex1.bash: Advent2020 game, day 15/games 1 and 2.
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# ===> Too slow for exercise 2, needed to rewrite the algorithm.
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CMD=${0##*/}
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#shopt -s extglob
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declare -A prev nums
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declare -i cur=0 last
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function print_binary() {
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local -i num=$1 exp
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local str="" format="%0${2}d"
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for ((exp=1; num>exp; exp<<=1)); do
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if ((num & exp)); then
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str=1"$str"
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else
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str=0"$str"
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fi
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echo " str=$str"
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done
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printf "$format" $str
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}
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function print_array() {
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local -i i
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printf "last: %d\n" "$last"
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printf "nums:\n"
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for i in "${!nums[@]}"; do
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printf " %6d => %d\n" "$i" "${nums[$i]}" >&2
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if [[ -v prev[$i] ]]; then
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printf " prev => %d\n" "${prev[$i]}" >&2
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fi
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done
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}
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TARGET=$1
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IFS=","
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read -r line
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set -- $line
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while (($# > 0)); do
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nums[$1]=$cur
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last=$1
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((cur++))
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shift
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done
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for ((; cur != TARGET; ++cur)); do
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diff=0
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if [[ -v prev[$last] ]]; then
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((diff=nums[$last]-prev[$last]))
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prev[$last]=${nums[$last]}
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fi
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[[ -v nums[$diff] ]] && prev[$diff]=${nums[$diff]}
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nums[$diff]=$cur
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last=$diff
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done
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printf "%s : res=%d\n" "$CMD" "$last"
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exit 0
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