62 lines
883 B
Bash
Executable File
62 lines
883 B
Bash
Executable File
#!/bin/bash
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#
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# ex1.bash: Advent2020 game, day 15/game 1.
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CMD=${0##*/}
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#shopt -s extglob
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declare -A prev
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declare -i cur=1 last previous
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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 "${!prev[@]}"; do
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printf " prev[%d] => %d\n" "$i" "${prev[$i]}" >&2
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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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prev[$1]=$cur
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last=$1
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((cur++))
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shift
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done
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for ((previous=0; cur <= TARGET; ++cur)); do
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if ((previous)); then
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((diff=cur-previous-1))
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else
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diff=0
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fi
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((previous=prev[$diff]))
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prev[$diff]=$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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