Day 15

15/02.sh

@@ -0,0 +1,60 @@
+#!/bin/bash
+
+lines=()
+grid=()
+risks_grid=()
+i_max=0
+j_max=0
+while read line; do
+  lines+=( $line )
+done
+
+for ((grid_iter_i=0; grid_iter_i<5; grid_iter_i++)); do
+  for line in ${lines[@]}; do
+    j_max=${#line}
+    for ((grid_iter_j=0; grid_iter_j<5; grid_iter_j++)); do
+      for ((j=0; j<j_max; j++)); do
+        grid+=( $(((${line:$j:1}-1+grid_iter_j+grid_iter_i)%9+1)) )
+        risks_grid+=( -1 )
+      done
+    done
+    i_max=$((i_max+1))
+    j_max=$((j_max*5))
+  done
+done
+
+risks_grid[0]=0
+detected_paths=1
+iter=0
+while [ $detected_paths -eq 1 ]; do
+  detected_paths=0
+  for ((i=0; i<i_max; i++)); do
+    for ((j=0; j<j_max; j++)); do
+      lowest_risk=$((9*i_max*j_max))
+      if [ $j -gt 0 ] && [ ${risks_grid[$((i*j_max+j-1))]} -lt $lowest_risk ] \
+              && [ ${risks_grid[$((i*j_max+j-1))]} -ge 0 ]; then
+        lowest_risk=${risks_grid[$((i*j_max+j-1))]}
+      fi
+      if [ $j -lt $((j_max-1)) ] && [ ${risks_grid[$((i*j_max+j+1))]} -lt $lowest_risk ] \
+              && [ ${risks_grid[$((i*j_max+j+1))]} -ge 0 ]; then
+        lowest_risk=${risks_grid[$((i*j_max+j+1))]}
+      fi
+      if [ $i -gt 0 ] && [ ${risks_grid[$(((i-1)*j_max+j))]} -lt $lowest_risk ] \
+              && [ ${risks_grid[$(((i-1)*j_max+j))]} -ge 0 ]; then
+        lowest_risk=${risks_grid[$(((i-1)*j_max+j))]}
+      fi
+      if [ $i -lt $((i_max-1)) ] && [ ${risks_grid[$(((i+1)*j_max+j))]} -lt $lowest_risk ] \
+              && [ ${risks_grid[$(((i+1)*j_max+j))]} -ge 0 ]; then
+        lowest_risk=${risks_grid[$(((i+1)*j_max+j))]}
+      fi
+      if [ ${risks_grid[$((i*j_max+j))]} -lt 0 ] \
+	      || [ ${risks_grid[$((i*j_max+j))]} -gt $((grid[i*j_max+j]+lowest_risk)) ]; then
+        risks_grid[$((i*j_max+j))]=$((grid[i*j_max+j]+lowest_risk))
+	detected_paths=1
+      fi
+    done
+  done
+  iter=$((iter+1))
+done
+
+echo ${risks_grid[$((i_max*j_max-1))]}