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380.cpp
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380.cpp
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__________________________________________________________________________________________________
sample 44 ms submission
static const int _ = [](){
ios::sync_with_stdio(false);
cin.tie(nullptr);
return 0;
}();
class RandomizedSet {
private:
// Number of values in set.
int Size = 0;
// Map values in the set to their sequential buckets for random access.
std::unordered_map<int, int *> ValToBucket;
// Bucket of each value in the set. Used for random access.
std::deque<int> Buckets;
// Random number generator.
std::random_device RandDevice;
std::mt19937 RandGen;
public:
RandomizedSet() : RandGen(RandDevice()) {}
// Inserts a value to the set.
//
// \return If the set did not already contain the specified element.
bool insert(int Val) {
auto InsertResult = ValToBucket.emplace(Val, nullptr);
if (!InsertResult.second)
return false;
Buckets.push_back(Val);
InsertResult.first->second = &Buckets.back();
Size++;
return true;
}
// Removes a value from the set.
// \return If the set contained the specified element.
bool remove(int Val) {
auto FindResult = ValToBucket.find(Val);
if (FindResult == ValToBucket.end())
return false;
const int SwapVal = Buckets.back();
std::swap(Buckets.back(), *FindResult->second);
ValToBucket[SwapVal] = FindResult->second;
ValToBucket.erase(FindResult);
Buckets.pop_back();
Size--;
return true;
}
// \return A random element from the set.
int getRandom() {
std::uniform_int_distribution<int> Rand(0, Size - 1);
return Buckets[Rand(RandGen)];
}
};
/**
* Your RandomizedSet object will be instantiated and called as such:
* RandomizedSet* obj = new RandomizedSet();
* bool param_1 = obj->insert(val);
* bool param_2 = obj->remove(val);
* int param_3 = obj->getRandom();
*/
__________________________________________________________________________________________________
sample 21240 kb submission
class RandomizedSet {
public:
/** Initialize your data structure here. */
RandomizedSet() {
}
/** Inserts a value to the set. Returns true if the set did not already contain the specified element. */
bool insert(int val) {
if (count(vec.begin(),vec.end(),val)) return false;
else {
vec.push_back(val);
return true;
}
}
/** Removes a value from the set. Returns true if the set contained the specified element. */
bool remove(int val) {
auto it=find(vec.begin(),vec.end(),val);
if (it != vec.end())
{
vec.erase(it);
return true;
} else {
return false;
}
}
/** Get a random element from the set. */
int getRandom() {
return vec[rand()%vec.size()];
}
private:
vector<int> vec;
};
/**
* Your RandomizedSet object will be instantiated and called as such:
* RandomizedSet obj = new RandomizedSet();
* bool param_1 = obj.insert(val);
* bool param_2 = obj.remove(val);
* int param_3 = obj.getRandom();
*/
__________________________________________________________________________________________________