Day 19

19/01.sh

@@ -0,0 +1,116 @@
+#!/bin/bash
+
+declare -A scanners
+declare -A beacons
+scanner_i=-1
+n_scanners=0
+scanners_beacons_n=()
+declare -A placed_scanners
+while read line; do
+  if [[ $line == "---"*"---" ]]; then
+    scanner_i=$((scanner_i+1))
+    n_scanners=$((n_scanners+1))
+    scanners_beacons_n+=(0)
+    placed_scanners[$scanner_i]=0
+  elif ! [ -z "$line" ]; then
+    scanners[$scanner_i,${scanners_beacons_n[$scanner_i]}]=$line
+    scanners_beacons_n[$scanner_i]=$((scanners_beacons_n[scanner_i]+1))
+  fi
+done
+
+for ((i=0;i<scanners_beacons_n[0];i++)); do
+  beacons[${scanners[0,$i]}]=1
+done
+placed_scanners[0]=1
+n_placed_scanners=1
+
+declare -A coordinates
+coordinates=( \
+        [0,x]=x [0,y]=y [0,z]=z \
+        [1,x]=x [1,y]=z [1,z]=-y \
+        [2,x]=x [2,y]=-y [2,z]=-z \
+        [3,x]=x [3,y]=-z [3,z]=y \
+        [4,x]=-x [4,y]=y [4,z]=-z \
+        [5,x]=-x [5,y]=-z [5,z]=-y \
+        [6,x]=-x [6,y]=-y [6,z]=z \
+        [7,x]=-x [7,y]=z [7,z]=y \
+        [8,x]=y [8,y]=-x [8,z]=z \
+        [9,x]=y [9,y]=z [9,z]=x \
+        [10,x]=y [10,y]=x [10,z]=-z \
+        [11,x]=y [11,y]=-z [11,z]=-x \
+        [12,x]=-y [12,y]=-x [12,z]=-z \
+        [13,x]=-y [13,y]=-z [13,z]=x \
+        [14,x]=-y [14,y]=x [14,z]=z \
+        [15,x]=-y [15,y]=z [15,z]=-x \
+        [16,x]=z [16,y]=y [16,z]=-x \
+        [17,x]=z [17,y]=-x [17,z]=-y \
+        [18,x]=z [18,y]=-y [18,z]=x \
+        [19,x]=z [19,y]=x [19,z]=y \
+        [20,x]=-z [20,y]=y [20,z]=x \
+        [21,x]=-z [21,y]=x [21,z]=-y \
+        [22,x]=-z [22,y]=-y [22,z]=-x \
+        [23,x]=-z [23,y]=-x [23,z]=y \
+)
+
+while [ $n_placed_scanners -lt $n_scanners ]; do
+  n_overlapping_beacons=0
+  for placed_beacon in ${!beacons[@]}; do
+    x_placed_beacon=${placed_beacon%%,*}
+    y_placed_beacon=${placed_beacon%,*}
+    y_placed_beacon=${y_placed_beacon#*,}
+    z_placed_beacon=${placed_beacon##*,}
+    for ((i_scanners=1;i_scanners<n_scanners;i_scanners++)); do
+      if [ ${placed_scanners[$i_scanners]} -eq 0 ]; then
+        for ((i_orientations=0;i_orientations<24;i_orientations++)); do
+          for ((i_matching_beacons=0;i_matching_beacons<scanners_beacons_n[$i_scanners];i_matching_beacons++)); do
+            matching_beacon_coordinate=${scanners[$i_scanners,$i_matching_beacons]}
+            x=${matching_beacon_coordinate%%,*}
+            y=${matching_beacon_coordinate%,*}
+            y=${y#*,}
+            z=${matching_beacon_coordinate##*,}
+            x_offset=$((x_placed_beacon-coordinates[$i_orientations,x]))
+            y_offset=$((y_placed_beacon-coordinates[$i_orientations,y]))
+            z_offset=$((z_placed_beacon-coordinates[$i_orientations,z]))
+            n_overlapping_beacons=0
+            for ((i_beacons=0;i_beacons<scanners_beacons_n[$i_scanners];i_beacons++)); do
+              beacon_coordinate=${scanners[$i_scanners,$i_beacons]}
+              x=${beacon_coordinate%%,*}
+              y=${beacon_coordinate%,*}
+              y=${y#*,}
+              z=${beacon_coordinate##*,}
+              curr_coordinates=$((coordinates[$i_orientations,x]+x_offset)),$((coordinates[$i_orientations,y]+y_offset)),$((coordinates[$i_orientations,z]+z_offset))
+              if ! [ -z ${beacons[$curr_coordinates]} ]; then
+                n_overlapping_beacons=$((n_overlapping_beacons+1))
+              fi
+            done
+            if [ $n_overlapping_beacons -ge 12 ]; then
+              placed_scanners[$i_scanners]=1
+              n_placed_scanners=$((n_placed_scanners+1))
+              for ((i_beacons=0;i_beacons<scanners_beacons_n[$i_scanners];i_beacons++)); do
+                beacon_coordinate=${scanners[$i_scanners,$i_beacons]}
+                x=${beacon_coordinate%%,*}
+                y=${beacon_coordinate%,*}
+                y=${y#*,}
+                z=${beacon_coordinate##*,}
+                curr_coordinates=$((coordinates[$i_orientations,x]+x_offset)),$((coordinates[$i_orientations,y]+y_offset)),$((coordinates[$i_orientations,z]+z_offset))
+                beacons[$curr_coordinates]=1
+              done
+              break
+            fi
+          done
+          if [ $n_overlapping_beacons -ge 12 ]; then
+            break
+          fi
+        done
+      fi
+      if [ $n_overlapping_beacons -ge 12 ]; then
+        break
+      fi
+    done
+    if [ $n_overlapping_beacons -ge 12 ]; then
+      break
+    fi
+  done
+done
+
+echo ${#beacons[@]}