[InterviewBit] Simple Queries

Simple Queries

  • Time : O(nsqrtn + nlogn)
  • Space : O(n)
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long long helper(long long n) {
long long res = 1, mod = 1e9 + 7;
for(int i = 1; i <= sqrt(n); i++) {
if(n % i) continue;
res = (res * i) % mod;
if(i * i != n) res = (res * (n/i)) % mod;
}
return res;
}

vector<int> Solution::solve(vector<int> &A, vector<int> &B) {
vector<pair<long long,long long>> st;
A.push_back(INT_MAX);
unordered_map<long long, long long> freq;
for(int i = 0; i < A.size(); i++) {
int cnt = 1;
while(!st.empty() and A[st.back().second] <= A[i]) {
auto [c, idx] = st.back(); st.pop_back();
cnt += c;
freq[A[idx]] += c * (i - idx);
}
st.push_back({cnt,i});
}
unordered_map<long long, long long> P;
for(auto& [n, cnt] : freq) P[helper(n)] += cnt;
vector<pair<long long, long long>> S;
for(auto& [k,v] : P) S.push_back({k,v});
sort(rbegin(S), rend(S));
vector<long long> psum {0};

for(int i = 0; i < S.size(); i++) {
auto [_, cnt] = S[i];
psum.push_back(psum.back() + cnt);
}

vector<int> res;
for(int i = 0; i < B.size(); i++) {
int f = B[i] - 1;
auto idx = upper_bound(begin(psum), end(psum), f) - begin(psum) - 1;
res.push_back(S[idx].first);
}
return res;
}

Author: Song Hayoung
Link: https://songhayoung.github.io/2022/09/06/PS/interviewbit/simple-queries/
Copyright Notice: All articles in this blog are licensed under CC BY-NC-SA 4.0 unless stating additionally.