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| class NumberContainers {
private final Map<Integer, Integer> indexToNumMap;
private final Map<Integer, TreeSet<Integer>> numToIndexTreeSetMap;
public NumberContainers() {
this.indexToNumMap = new HashMap<>();
this.numToIndexTreeSetMap = new HashMap<>();
}
public void change(int index, int number) {
Integer prevNum = indexToNumMap.put(index, number);
if (prevNum != null) {
numToIndexTreeSetMap.get(prevNum).remove(index);
}
numToIndexTreeSetMap.computeIfAbsent(number, key -> new TreeSet<>())
.add(index);
}
public int find(int number) {
TreeSet<Integer> indexSet = numToIndexTreeSetMap.get(number);
if (indexSet == null || indexSet.isEmpty()) {
return -1;
}
return indexSet.first();
}
}
|
References
2349. Design a Number Container System