2015/advent21.sh

   1 read _ _ boss_hit
   2 read _ boss_damage
   3 read _ boss_armor
   4 # battle hit damage armor boss_hit damage armor # return 0 if player beats boss
   5 battle() {
   6     echo "battle $@"
   7     p=$1 b=$4
   8     att=$(($2-$6)) def=$(($5-$3))
   9     (( att < 1 )) && att=1
  10     (( def < 1 )) && def=1
  11     turn=0
  12     while :; do
  13         b=$((b-att))
  14         (( b > 0 )) || return 0;
  15         p=$((p-def))
  16         (( p > 0 )) || return 1;
  17     done
  18 }
  19 weapon=('8 4 0' '10 5 0' '25 6 0' '40 7 0' '74 8 0')
  20 armor=('0 0 0' '13 0 1' '31 0 2' '53 0 3' '75 0 4' '102 0 5')
  21 ring=('0 0 0' '25 1 0' '50 2 0' '100 3 0' '20 0 1' '40 0 2' '80 0 3')
  22 lowest=99999
  23 highest=0
  24 # prep w w w a a a r1 r1 r1 r2 r2 r2 # buy stuff to prepare for battle
  25 prep() {
  26     echo "prep $@"
  27     cost=$(($1 + $4 + $7 + ${10}))
  28     if battle 100 $(($2 + $5 + $8 + ${11})) $(($3 + $6 + $9 + ${12})) \
  29               $boss_hit $boss_damage $boss_armor; then
  30         echo "win, after spending $cost"
  31         [[ $cost -lt $lowest ]] && lowest=$cost
  32     else
  33         echo "loss, after spending $cost"
  34         [[ $cost -gt $highest ]] && highest=$cost
  35     fi
  36 }
  37 count=0
  38 for w in ${!weapon[*]}; do
  39     for a in ${!armor[*]}; do
  40         for r1 in ${!ring[*]}; do
  41             for r2 in ${!ring[*]}; do
  42                 (( r1 ? r1 == r2 : r2 )) && continue
  43                 : $((count++))
  44                 prep ${weapon[w]} ${armor[a]} ${ring[r1]} ${ring[r2]}
  45             done
  46         done
  47     done
  48 done
  49 echo "after trying $count scenarios, cheapest win costs $lowest"
  50 echo "most expensive loss is $highest"