leetcode-algorithms/src/SumOfUniqueElements.java at master · anishLearnsToCode/leetcode-algorithms · GitHub

37 lines (33 loc) · 1.11 KB

import java.util.Collection;

import java.util.HashMap;

import java.util.HashSet;

import java.util.Map;

import java.util.Set;

public class SumOfUniqueElements {

public int sumOfUnique(int[] nums) {

final Set<Integer> uniqueElements = uniqueElements(nums);

return sum(uniqueElements);

}

private Set<Integer> uniqueElements(int[] array) {

final Map<Integer, Integer> frequencies = getFrequencies(array);

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

for (Map.Entry<Integer, Integer> entry : frequencies.entrySet()) {

if (entry.getValue() == 1) set.add(entry.getKey());

}

return set;

}

private Map<Integer, Integer> getFrequencies(int[] array) {

final Map<Integer, Integer> frequencies = new HashMap<>();

for (int element : array) {

frequencies.put(element, frequencies.getOrDefault(element, 0) + 1);

}

return frequencies;

}

private int sum(Collection<Integer> collection) {

int sum = 0;

for (int element : collection) {

sum += element;

}

return sum;

}

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