int nthSuperUglyNumber(int n, vector<int>& primes) {
vector<int> uglies(n), ugly_by_prime(primes), idx(primes.size());
uglies[0] = 1;
for (int i = 1; i < n; ++i) {
int min_val = *min_element(ugly_by_prime.begin(), ugly_by_prime.end());
uglies[i] = min_val;
for (int k = 0; k < primes.size(); ++k) {
if (min_val == ugly_by_prime[k]) {
ugly_by_prime[k] = primes[k] * uglies[++idx[k]];
}
}
}
return uglies[n - 1];
}
int nthSuperUglyNumber(int n, vector<int>& primes) {
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> heap;
vector<int> uglies(n), idx(primes.size()), ugly_by_last_prime(n);
uglies[0] = 1;
for (int i = 0; i < primes.size(); ++i) {
heap.emplace(primes[i], i);
}
for (int i = 1; i < n; ++i) {
int k;
tie(uglies[i], k) = heap.top();
heap.pop();
ugly_by_last_prime[i] = k;
while (ugly_by_last_prime[++idx[k]] > k); // average time: O(k)
heap.emplace(uglies[idx[k]] * primes[k], k);
}
return uglies[n - 1];
}
int nthUglyNumber(int n){
vector<int> uglies(n);
uglies[0] = 1;
int f2=2, f3=3, f5=5;
int idx2=0, idx3=0, idx5=0;
for(int i=1; i<n; i++){
int min_val = min(min(f2,f3),f5);
uglies[i] = min_val;
if (min_val%2==0) {
f2 = 2*uglies[++idx2];
}
if (min_val%3==0) {
f3 = 3*uglies[++idx3];
}
if (min_val%5==0) {
f5 = 5*uglies[++idx5];
}
}
return uglies[n-1];
}
int nthSuperUglyNumber(int n, vector<int>& primes) {
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> heap;
vector<int> uglies(n), idx(primes.size());
uglies[0] = 1;
for (int k = 0; k < primes.size(); ++k) {
heap.emplace(primes[k], k);
}
for (int i = 1; i < n; ++i) {
int k;
tie(uglies[i], k) = heap.top();
while (heap.top().first == uglies[i]) { // worst time: O(klogk)
tie(uglies[i], k) = heap.top();
heap.pop();
heap.emplace(primes[k] * uglies[++idx[k]], k);
}
}
return uglies[n - 1];
}
int nthSuperUglyNumber(int n, vector<int>& primes) {
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> heap;
unordered_set<int> ugly_set{1};
vector<int> uglies(n), idx(primes.size());
uglies[0] = 1;
for (int k = 0; k < primes.size(); ++k) {
heap.emplace(primes[k], k);
ugly_set.emplace(primes[k]);
}
for (int i = 1; i < n; ++i) {
int k;
tie(uglies[i], k) = heap.top();
heap.pop();
while (ugly_set.count(primes[k] * uglies[idx[k]])) {
++idx[k];
}
heap.emplace(primes[k] * uglies[idx[k]], k);
ugly_set.emplace(primes[k] * uglies[idx[k]]);
}
return uglies[n - 1];
}
