C
c++ leetcode 380 Insert Delete GetRandom o(1) solution code
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2021. 7. 17. 01:39
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class RandomizedSet {
public:
/** Initialize your data structure here. */
unordered_map<int, int> hashmap;
vector<int> intarray;
RandomizedSet() {
}
/** Inserts a value to the set. Returns true if the set did not already contain the specified element. */
bool insert(int val) {
if (hashmap.count(val) == 0)
{
intarray.emplace_back(val);
hashmap[val] = (int)intarray.size()-1;
return true;
}
else
return false;
}
/** Removes a value from the set. Returns true if the set contained the specified element. */
bool remove(int val) {
if (hashmap.count(val) == 0)
return false;
else
{
int idx = hashmap[val];
intarray[idx] = intarray.back();
hashmap[intarray[idx]] = idx;
intarray.pop_back();
hashmap.erase(val);
}
return true;
}
/** Get a random element from the set. */
int getRandom() {
int sizeArray = (int)intarray.size();
//cout << "size of array : " << sizeArray << endl;
int ran_num = rand() % sizeArray;
//cout << "ran num : " << ran_num << endl;
return intarray[ran_num];
}
};
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