# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
1251996 | Gabp | Souvenirs (IOI25_souvenirs) | C++20 | 0 ms | 0 KiB |
#include<bits/stdc++.h>
using namespace std;
void buy_souvenirs(int n, long long int P0) {
vector<int> cnt(n, 0);
vector<long long int> vals(n, -1);
auto find_min = [&](long long int total, int sz) -> long long int {
long long int lo = sz, hi = total;
long long int res;
while (lo <= hi) {
long long int mid = lo + (hi - lo) / 2;
long long int last = mid - sz + 1;
long long int sum = (mid + last) * sz / 2;
long long int left = total - sum;
if (left >= last - 1) {
lo = mid + 1;
} else {
res = mid;
hi = mid - 1;
}
}
return res;
};
long long int prev = P0;
vector<pair<vector<int>,long long int>> hist;
vector<long long int> queries;
for (int i = 1; i < n; i++) {
auto data = transaction(prev - 1);
hist.push_back(data);
queries.push_back(prev - 1);
auto [list, m] = data;
assert(list[0] == i);
for (auto j: list) cnt[j]++;
if (list.size() == 1) {
vals[i] = prev - 1 - m;
prev = vals[i];
continue;
}
if (list.size() == n - i) {
long long int total = prev - 1 - m;
long long int lo = n - i, hi = total;
while (lo <= hi) {
long long int mid = lo + (hi - lo) / 2;
long long int sum = (2 * mid + 1 - i + n) * (n - i) / 2;
if (total - sum <= 0) {
prev = mid;
hi = mid - 1;
} else {
lo = mid + 1;
}
}
continue;
}
int sz = 1;
while (sz < list.size() && list[sz] == i + sz) sz++;
prev = find_min(prev - 1, sz);
}
for (int i = n - 1; i > 0; i--) {
if (val[i] != -1) continue;
val[i] = queries[i - 1];
auto [list, m] = hist[i - 1];
val[i] -= m;
for (int j = 1; j < list.size(); j++) val[i] -= val[list[j]];
}
for (int i = 1; i < n; i++) {
for (int j = cnt[i]; j < i; j++) {
transaction(val[i]);
}
}
}