From bdd1421637e7bbeeb68505741799ae95736a8865 Mon Sep 17 00:00:00 2001
From: Pierre Jeanjean <rhiobet@gmail.com>
Date: Tue, 21 Dec 2021 14:47:09 +0100
Subject: [PATCH] Day 21

---
 21/01.sh |  32 ++++++++++++++++
 21/02.sh | 113 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 145 insertions(+)
 create mode 100755 21/01.sh
 create mode 100755 21/02.sh

diff --git a/21/01.sh b/21/01.sh
new file mode 100755
index 0000000..2852693
--- /dev/null
+++ b/21/01.sh
@@ -0,0 +1,32 @@
+#!/bin/bash
+
+positions=()
+scores=()
+
+while read line; do
+  positions+=( $(sed 's/^.* \([0-9]*\)$/\1/' <<< $line) )
+  scores+=( 0 )
+done
+
+dice_next_value=1
+player_index=0
+finished=0
+n_rolls=0
+
+while [ $finished -eq 0 ]; do
+  roll=$((dice_next_value+dice_next_value+1+(dice_next_value+1)%100+1))
+  dice_next_value=$(((dice_next_value+2)%100+1))
+  positions[$player_index]=$(((positions[player_index]+roll-1)%10+1))
+  scores[$player_index]=$((scores[player_index]+positions[player_index]))
+  if [ ${scores[$player_index]} -ge 1000 ]; then
+    finished=1
+  fi
+  player_index=$(((player_index+1)%${#positions[@]}))
+  n_rolls=$((n_rolls+3))
+done
+
+for score in ${scores[@]}; do
+  if [ $score -lt 1000 ]; then
+    echo $((score*n_rolls))
+  fi
+done
diff --git a/21/02.sh b/21/02.sh
new file mode 100755
index 0000000..00888f8
--- /dev/null
+++ b/21/02.sh
@@ -0,0 +1,113 @@
+#!/bin/bash
+
+declare -A positions
+declare -A scores
+declare -A victories
+read line
+start_position_1=$(sed 's/^.* \([0-9]*\)$/\1/' <<< $line)
+read line
+start_position_2=$(sed 's/^.* \([0-9]*\)$/\1/' <<< $line)
+positions[$start_position_1,$start_position_2]=1
+scores[0,0,$start_position_1,$start_position_2]=1
+victories[1]=0
+victories[2]=0
+
+rolls=( 0 0 0 1 3 6 7 6 3 1 )
+
+iter=0
+
+for ((iter=0;iter<21;iter++)); do
+  declare -A new_positions
+  declare -A new_scores
+  for position in ${!positions[@]}; do
+    for ((i=3;i<10;i++)); do
+      position_1=${position%,*}
+      position_2=${position#*,}
+      new_position_1=$(((position_1+i-1)%10+1))
+      new_positions[$new_position_1,$position_2]=$((${new_positions[$new_position_1,$position_2]}+${positions[$position]}*rolls[i]))
+      for score in ${!scores[@]}; do
+        score_1=${score%%,*}
+        score_2=${score#*,}
+        score_2=${score_2%%,*}
+        score_position_1=${score%,*}
+        score_position_1=${score_position_1##*,}
+        score_position_2=${score##*,}
+        if [ $score_position_1 -eq $position_1 ] && [ $score_position_2 -eq $position_2 ]; then
+          new_score_1=$((score_1+new_position_1))
+          if [ $new_score_1 -ge 21 ]; then
+            victories[1]=$((${victories[1]}+${scores[$score]}*rolls[i]))
+            new_positions[$new_position_1,$position_2]=$((${new_positions[$new_position_1,$position_2]}-${scores[$score]}))
+          else
+            new_scores[$new_score_1,$score_2,$new_position_1,$position_2]=$((${new_scores[$new_score_1,$score_2,$new_position_1,$position_2]}+${scores[$score]}*rolls[i]))
+          fi
+        fi
+      done
+    done
+  done
+  
+  unset positions
+  declare -A positions
+  for position in ${!new_positions[@]}; do
+    positions[$position]=${new_positions[$position]}
+    positions[$position]=${new_positions[$position]}
+  done
+  unset new_positions
+  unset scores
+  declare -A scores
+  for score in ${!new_scores[@]}; do
+    scores[$score]=${new_scores[$score]}
+    scores[$score]=${new_scores[$score]}
+  done
+  unset new_scores
+
+  declare -A new_positions
+  declare -A new_scores
+  for position in ${!positions[@]}; do
+    for ((i=3;i<10;i++)); do
+      position_1=${position%,*}
+      position_2=${position#*,}
+      new_position_2=$(((position_2+i-1)%10+1))
+      new_positions[$position_1,$new_position_2]=$((${new_positions[$position_1,$new_position_2]}+${positions[$position]}*rolls[i]))
+      for score in ${!scores[@]}; do
+        score_1=${score%%,*}
+        score_2=${score#*,}
+        score_2=${score_2%%,*}
+        score_position_1=${score%,*}
+        score_position_1=${score_position_1##*,}
+        score_position_2=${score##*,}
+        if [ $score_position_1 -eq $position_1 ] && [ $score_position_2 -eq $position_2 ]; then
+          new_score_2=$((score_2+new_position_2))
+          if [ $new_score_2 -ge 21 ]; then
+            victories[2]=$((${victories[2]}+${scores[$score]}*rolls[i]))
+            new_positions[$position_1,$new_position_2]=$((${new_positions[$position_1,$new_position_2]}-${scores[$score]}))
+          else
+            new_scores[$score_1,$new_score_2,$position_1,$new_position_2]=$((${new_scores[$score_1,$new_score_2,$position_1,$new_position_2]}+${scores[$score]}*rolls[i]))
+          fi
+        fi
+      done
+    done
+  done
+  
+  unset positions
+  declare -A positions
+  for position in ${!new_positions[@]}; do
+    positions[$position]=${new_positions[$position]}
+    positions[$position]=${new_positions[$position]}
+  done
+  unset new_positions
+  unset scores
+  declare -A scores
+  for score in ${!new_scores[@]}; do
+    scores[$score]=${new_scores[$score]}
+    scores[$score]=${new_scores[$score]}
+  done
+  unset new_scores
+done
+
+most_victories=0
+for victory in ${victories[@]}; do
+  if [ $victory -gt $most_victories ]; then
+    most_victories=$victory
+  fi
+done
+echo $most_victories