76 lines
1.2 KiB
Bash
Executable File
76 lines
1.2 KiB
Bash
Executable File
#!/bin/bash
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#
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# ex1.bash: Advent2020 game, day 9/game 2.
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CMD=${0##*/}
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shopt -s extglob
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declare -i N=5 SIZE
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declare -a LIST=()
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function push25 () {
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local i
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for ((i=0; i<25; ++i)); do
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read -r i
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LIST+=("$i")
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done
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}
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function push() {
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local i
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while read -r i; do
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LIST+=("$i")
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done
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SIZE=${#LIST[@]}
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}
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function badnum() {
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local -i cur="$1" i j
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local -i res=${LIST[$cur]}
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local -i start=$((cur-N-1))
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for ((i=start; i<cur; ++i)); do
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for ((j=i+1; j<cur; ++j)); do
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if (((LIST[i]+LIST[j]) == res)); then
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return 0
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fi
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done
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done
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return 1
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}
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function findsum() {
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local -i target=$1 start=$2 i
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local -i sum=0
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local -i small=${LIST[$start]}
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local -i high=$small
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for ((i=start; i<SIZE && sum<target; ++i)); do
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((cur=${LIST[$i]}))
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((sum+=cur))
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((cur<small)) && small=$cur
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((cur>high)) && high=$cur
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if ((sum==target)); then
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echo $((small+high))
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return 0
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fi
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done
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return 1
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}
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[[ $# = 1 ]] && N=$1
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push
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declare -i i target num
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for ((i=N; i<SIZE; ++i)); do
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badnum $i || break
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done
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target="${LIST[$i]}"
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for ((i=0; i<SIZE; ++i)); do
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num=$(findsum "$target" $i) && break
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done
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printf "%s : res=%d sum=%d\n" "$CMD" "$target" "$num"
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exit 0
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