How to find a key based on value in dictionary?

#!/bin/bash
cd /pg
declare -A arr
file=`ls -l |awk '{print $9}'`
#declare -A  test_dict
for i in $file
do
  #if [[ "$one" -eq "1" ]]; then
  one=`cat /pg/$i | wc -l`
  if [[ "$one" -eq "1" ]]; then
     key=$(awk 'NR==1{print $7}' "/pg/$i")
     value=$(awk 'NR==1{print $8}' "/pg/$i")
     #echo $key
     #echo $value
     arr["$key"]=$value
  else
     key=$(awk 'NR==1{print $7}' "/pg/$i")
     value=$(awk 'NR==1{print $8}' "/pg/$i")
     value1=$(awk 'NR==2{print $8}' "/pg/$i")
     c=$(($value+$value1))
     arr["$key"]=$c
  fi
done
echo ${arr[@]}
max=0
for j in "${arr[@]}";do
    if (( $j > max));then
            max=$j
    fi
done
echo "max:$max"
echo  "${!arr[@]}"

From the above code I'm appending "key","values" to the dictionary and getting maxium value, so now I need to print the "key" based on "max" value. value's are "120 60 75 60" maxium values is "120" key's are "hari azureuser cnu root" expecting out put is : hari becasue maxium value[120] came from "hari". Please help me to achieve the same.

Loop over keys:

max=0
for k in "${!arr[@]}";do
    if (( ${arr["$k"]} > max));then
            max="${arr["$k"]}"
            max_key="$k"
    fi
done
echo "$max_key"

However, there are better options to do such things than using a bash script.