+#!/bin/bash
+
+set -u
+
+declare -a octopusses
+declare -A flashed=()
+declare -a to_flash=()
+
+filename="${1:-small.txt}"
+iterations="${2:-2}"
+step_display="${3:-1}"
+
+exec 3<"$filename"
+
+width=0
+height=0
+
+while read -u 3 line; do
+ width=${#line}
+ for (( a=0; a<$width; a++ )); do
+ octopusses+=(${line:$a:1})
+ done
+ ((height+=1))
+done
+
+get_offset() {
+ local x=$1
+ local y=$2
+
+ echo $((($y*$width)+$x))
+}
+
+flash_offset() {
+ local offset=$1
+ local x=$((offset%$width))
+ local y=$((offset/$width))
+
+ flash $x $y
+}
+
+flash() {
+ local x=$1
+ local y=$2
+
+ local offset=$(get_offset $x $y)
+
+ if [ "${flashed[$offset]+abc}" ]; then
+ return 0
+ fi
+ flashed[$offset]=1
+
+ for (( offsety=-1; offsety<=1; offsety++ )); do
+ for (( offsetx=-1; offsetx<=1; offsetx++ )); do
+ new_x=$(($x+$offsetx))
+ new_y=$(($y+$offsety))
+ if [ $new_x -eq $x ] && [ $new_y -eq $y ]; then
+ continue
+ fi
+ if [ $new_x -lt 0 ] || [ $new_x -ge $width ] || [ $new_y -lt 0 ] || [ $new_y -ge $height ]; then
+ continue
+ fi
+ # add one to the octopus
+ local __offset=$(get_offset $new_x $new_y)
+ ((octopusses[$__offset]+=1))
+ if [ ${octopusses[$__offset]} -gt 9 ]; then
+ to_flash+=($__offset)
+ fi
+ done
+ done
+}
+
+display_grid() {
+ for (( y=0; y<$height; y++ )); do
+ for (( x=0; x<$height; x++ )); do
+ if [ "${flashed[$(get_offset $x $y)]+abc}" ]; then
+ tput bold
+ echo -n "${octopusses[$(get_offset $x $y)]}"
+ tput sgr0
+ else
+ echo -n "${octopusses[$(get_offset $x $y)]}"
+ fi
+ done
+ echo
+ done
+}
+
+total_flashes=0
+
+echo "Step 0"
+display_grid
+echo
+
+all_flashed=-1
+
+do_loop() {
+ local i=$1
+ to_flash=()
+ # first, add 1 to everything
+ for (( y=0; y<$height; y++ )); do
+ for (( x=0; x<$width; x++ )); do
+ offset=$(get_offset $x $y)
+ ((octopusses[$offset]+=1))
+ done
+ done
+ # now go back through, but only play with the flashes
+ for (( y=0; y<$height; y++ )); do
+ for (( x=0; x<$width; x++ )); do
+ offset=$(get_offset $x $y)
+ if [ ${octopusses[$offset]} -gt 9 ]; then
+ flash $x $y
+ fi
+ done
+ done
+ # and a quick second spin, just incase
+ for (( y=0; y<$height; y++ )); do
+ for (( x=0; x<$width; x++ )); do
+ offset=$(get_offset $x $y)
+ if [ ${octopusses[$offset]} -gt 9 ]; then
+ to_flash+=($offset)
+ fi
+ done
+ done
+
+ while [ "${#to_flash[@]}" -gt 0 ]; do
+ indexes=("${!to_flash[@]}")
+ index=${indexes[0]}
+ flash_offset ${to_flash[$index]}
+ unset to_flash[$index]
+ done
+
+ for offset in "${!flashed[@]}"; do
+ ((total_flashes+=1))
+ octopusses[$offset]=0
+ done
+
+ if [ $((i % $step_display)) -eq 0 ]; then
+ echo "Step $i"
+ display_grid
+ echo
+ fi
+
+ if [ $(($width*$height)) -eq ${#flashed[@]} ]; then
+ all_flashed=$i
+ fi
+
+ for offset in "${!flashed[@]}"; do
+ unset flashed[$offset]
+ done
+}
+
+for (( i=1; i<=$iterations; i++ )); do
+ do_loop $i
+done
+
+echo "total flashes for $iterations: $total_flashes"
+
+i=$(($iterations))
+while [ $all_flashed -eq -1 ]; do
+ ((i+=1))
+ do_loop $i
+done
+
+echo "All flashed on step $i"
projects / advent-of-code-2021.git / commitdiff