Recursive trees - https://www.hackerrank.com/challenges/fractal-trees-all

recursive_trees.sh

read -r iterations
readonly iterations

declare -A arr
rows=63
cols=100

for ((i = 1; i <= rows; i++)); do
    for ((j = 1; j <= cols; j++)); do
        arr[$i,$j]=_
    done
done

function gen() {
    local x=$1
    local y=$2
    local d=$3
    local h=$4
    local hh=$((h/2))
    
    if [[ $d -eq 0 ]]; then
        return 1
    fi     
    
    for ((i = 1; i <= hh; i++)); do
        arr[$(($y+$i)),$x]="1"
        arr[$(($y+$hh+$i)),$(($x-$i))]="1"
        arr[$(($y+$hh+$i)),$(($x+$i))]="1"
    done
    
    gen $((x-hh)) $((y+h)) $((d-1)) $hh
    gen $((x+hh)) $((y+h)) $((d-1)) $hh
}

gen 50 0 $iterations 32

for ((i = rows; i >= 0; i--)); do
    for ((j = 1; j <= cols; j++)); do
        echo -n "${arr[$i,$j]}"
    done
    echo -e 
done