[Lesson] 2. Arrays - OddOccurrencesInArray

소스코드 

Map<Integer, Integer> counterMap = new HashMap<Integer, Integer>();
for(int i = 0 ; i < A.length ; i ++){
	if(!counterMap.containsKey(A[i])){
		counterMap.put(A[i], 1);
	}
	else{
		if( (counterMap.get(A[i]) + 1) % 2 == 0 ){
			counterMap.remove(A[i]);
		}
		else{
			counterMap.put(A[i], counterMap.get(A[i]) + 1);
		}
	}
}

int result = 0;
Iterator<Integer> keys = counterMap.keySet().iterator();
while( keys.hasNext() ){
	Integer key = keys.next();
	result = key;
}
return result;