package string;

import java.util.*;

import java.util.stream.Stream;

import static java.util.function.Function.identity;

import static java.util.stream.Collectors.*;

public class Question30 {

public static void main(String[] args) {

System.out.println(wordFrequency("AAABBCDA"));

System.out.println(wordFrequency_Compute("AAABBCDA"));

System.out.println("wordFrequency_Merge: "+wordFrequency_Merge("AAABBCDA"));

System.out.println(wordFrequency_Lambdas("AAABBCDA"));

List<Integer> list = List.of(1, 2, 1, 23, 34, 23, 1);

Set<Integer> set = new HashSet<>(list);

System.out.println(set);

}

private static Map<String, Integer> wordFrequency_Merge(String word) {

Map<String, Integer> map = new LinkedHashMap<>();

Arrays.stream(word.split("")).forEach(key -> map.merge(key, 1, (k1, v1) -> v1 + 1));

return map;

}

private static Map<Character, Integer> wordFrequency(String word) {

Map<Character, Integer> map = new HashMap<>();

for (int i = 0; i < word.length(); i++) {

char key = word.charAt(i);

if (map.containsKey(key))

map.put(key, (map.get(key) + 1));

else

map.put(key, 1);

}

return map;

}

private static Map<String, Integer> wordFrequency_Split(String word) {

Map<String, Integer> map = new HashMap<>();

for (String key:word.split("")) {

if (map.containsKey(key))

map.put(key, (map.get(key) + 1));

else

map.put(key, 1);

}

return map;

}

private static Map<Character, Integer> wordFrequency_Compute(String word) {

Map<Character, Integer> map = new TreeMap<>();

for (int i = 0; i < word.length(); i++) {

char key = word.charAt(i);

map.compute(key, (k1, v1) -> map.get(k1) == null ? 1 : v1 + 1);

}

return map;

}

private static Map<String, Integer> wordFrequency_Lambdas(String word) {

return Stream.of(word.split(""))

.collect(groupingBy(identity(), summingInt(val -> 1)));

}

private static Map<String, Long> wordFrequency_LambdasCounting(String word) {

return Stream.of(word.split(""))

.collect(groupingBy(identity(), counting()));

}

}