Day 17

17/01.sh

@@ -0,0 +1,50 @@
+#!/bin/bash
+
+read line
+target=( $(sed 's/^.*x=\(.*\)\.\.\(.*\), y=\(.*\)\.\.\(.*\)/\1 \2 \3 \4/' <<< $line) )
+
+possible_x=()
+for ((i=1;i<target[1];i++)); do
+  velocity_x=$i
+  position_x=0
+  while [ $velocity_x -gt 0 ] && [ $position_x -lt ${target[0]} ]; do
+    position_x=$((position_x+velocity_x))
+    velocity_x=$((velocity_x-1))
+  done
+  if [ $position_x -ge ${target[0]} ] && [ $position_x -le ${target[1]} ]; then
+    possible_x+=( $i )
+  fi
+done
+
+highest_y=0
+for ((i=0;i<${#possible_x[@]};i++)); do
+  temp_highest_y=0
+  possible_y=$((target[2]*(-1)-1))
+  for ((j=$possible_y;j>0;j--)); do
+    velocity_x=${possible_x[$i]}
+    velocity_y=$j
+    position_x=0
+    position_y=0
+    while [ $position_x -le ${target[1]} ] && [ $position_y -ge ${target[2]} ]; do
+      position_x=$((position_x+velocity_x))
+      position_y=$((position_y+velocity_y))
+      velocity_x=$((velocity_x-1))
+      if [ $velocity_x -lt 0 ]; then
+        velocity_x=0
+      fi
+      velocity_y=$((velocity_y-1))
+      if [ $position_y -gt $temp_highest_y ]; then
+        temp_highest_y=$position_y
+      fi
+      if [ $position_x -ge ${target[0]} ] && [ $position_y -ge ${target[2]} ] \
+              && [ $position_x -le ${target[1]} ] && [ $position_y -le ${target[3]} ]; then
+        if [ $temp_highest_y -gt $highest_y ]; then
+          highest_y=$temp_highest_y
+        fi
+        break
+      fi
+    done
+  done
+done
+
+echo $highest_y