#!/bin/bash
declare -A map
while read line
do
    arr=($line)
    for i in ${arr[@]}
    do
    if [-z ${map[$i]}]
    then 
        map[$i] = 1
    else
        ((map[$i]++))
    fi
    done
done < nowcoder.txt

for i in ${!map[@]}
do 
echo $i ${map[$i]}
done | sort -k 2