| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1093178 | shivansh0809 | Holiday (IOI14_holiday) | C++17 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include <bits/stdc++.h>
using namespace std;
double EPS = 1e-7;
#ifndef ONLINE_JUDGE
#include </mnt/c/Coding/Templates/Debug.h>
#else
#define debug(x...)
#endif
const int N = 100'005;
const int LN = 20;
struct PersistentSegTree
{ // Returns the sum of K largest elements in [l, r)
map<int, pair<int, int>> compress;
// add log2(Q) is storage needed after some update query
int L[LN * N], R[LN * N], S[LN * N], KS[LN * N];
int NEXT_FREE_INDEX = 1;
int roots[N];
int MX;
PersistentSegTree(int v[], int n) : MX(n)
{
int tl = 0, tr = n;
pair<int, int> sort_v[n];
for (int i = 0; i < n; i++)
sort_v[i] = {v[i], i};
sort(sort_v, sort_v + n, greater<pair<int, int>>());
int idx[n];
for (int i = 0; i < n; i++)
compress[i] = sort_v[i], idx[sort_v[i].second] = i;
roots[0] = build(tl, tr);
for (int i = 0; i < n; i++)
roots[i + 1] = update(roots[i], tl, tr, idx[i]);
}
int new_vertex(int s, int ks, int l, int r)
{
S[NEXT_FREE_INDEX] = s;
KS[NEXT_FREE_INDEX] = ks;
L[NEXT_FREE_INDEX] = l;
R[NEXT_FREE_INDEX] = r;
return NEXT_FREE_INDEX++;
}
int new_vertex(int l, int r)
{
S[NEXT_FREE_INDEX] = S[l] + S[r];
KS[NEXT_FREE_INDEX] = KS[l] + KS[r];
L[NEXT_FREE_INDEX] = l;
R[NEXT_FREE_INDEX] = r;
return NEXT_FREE_INDEX++;
}
int build(int tl, int tr)
{
if (tl == tr)
return new_vertex(0, 0, -1, -1);
int tm = (tl + tr) / 2;
return new_vertex(build(tl, tm), build(tm + 1, tr));
}
int update(int idx, int tl, int tr, int pos)
{
if (tl == tr)
return new_vertex(S[idx] + 1, KS[idx] + compress[pos].first, -1, -1);
int tm = (tl + tr) / 2;
if (pos <= tm)
return new_vertex(update(L[idx], tl, tm, pos), R[idx]);
else
return new_vertex(L[idx], update(R[idx], tm + 1, tr, pos));
}
long long find_kth(int vl, int vr, int tl, int tr, int k)
{
if (tl == tr)
return KS[vr] - KS[vl];
int tm = (tl + tr) / 2;
int left_count = S[L[vr]] - S[L[vl]];
if (left_count >= k)
return find_kth(L[vl], L[vr], tl, tm, k);
return KS[L[vr]] - KS[L[vl]] + find_kth(R[vl], R[vr], tm + 1, tr, k - left_count);
}
long long find_kth(int l, int r, int k)
{
return find_kth(roots[l], roots[r], 0, MX, k);
}
};
long long int findMaxAttraction(int n, int start, int d, int attraction[])
{
long long int ans = 0;
PersistentSegTree pst(attraction, n);
function<long long(int, int)> C1 = [&](int k, int mid) -> long long
{
int days_rem = d - (mid - k + start - k);
if (days_rem <= 0)
return 0;
return pst.find_kth(k, mid + 1, days_rem);
// return mid - k;
};
function<long long(int, int)> C2 = [&](int mid, int k) -> long long
{
int days_rem = d - (k - mid + k - start);
if (days_rem <= 0)
return 0;
return pst.find_kth(mid, k + 1, days_rem);
// return k - mid;
};
// function<void(int, int, int, int)> dncg = [&](int l, int r, int optl, int optr)
// {
// if (l > r)
// return;
// int mid = (l + r) >> 1;
// pair<long long, int> best = {-1, -1};
// for (int k = optl; k <= min(mid, optr); k++)
// best = max(best, {C1(k, mid), k});
// // debug(dp, best, ndp);
// // debug(ans, best, mid);
// ans = max(best.first, ans);
// int opt = best.second;
// dncg(l, mid - 1, optl, opt);
// dncg(mid + 1, r, opt, optr);
// };
// function<void(int, int, int, int)> dncs = [&](int l, int r, int optl, int optr)
// {
// if (l > r)
// return;
// int mid = (l + r) >> 1;
// pair<long long, int> best = {-1, -1};
// for (int k = optr; k >= max(mid, optl); k--)
// best = max(best, {C2(mid, k), k});
// // debug(dp, best, ndp);
// // debug(ans, best, mid);
// ans = max(best.first, ans);
// int opt = best.second;
// dncs(l, mid - 1, optl, opt);
// dncs(mid + 1, r, opt, optr);
// };
if (d == 0)
return 0;
ans = attraction[start];
vector<array<int, 4>> dncg, dncs;
dncg.push_back({start + 1, n - 1, 0, start});
dncs.push_back({0, start - 1, start, n - 1});
while (!dncg.empty())
{
auto [l, r, optl, optr] = dncg.back();
dncg.pop_back();
if (l > r)
continue;
int mid = (l + r) >> 1;
pair<long long, int> best = {-1, -1};
for (int k = optl; k <= min(mid, optr); k++)
best = max(best, {C1(k, mid), k});
// debug(dp, best, ndp);
// debug(ans, best, mid);
ans = max(best.first, ans);
int opt = best.second;
dncg.push_back({mid + 1, r, opt, optr});
dncg.push_back({l, mid - 1, optl, opt});
}
while (!dncs.empty())
{
auto [l, r, optl, optr] = dncs.back();
dncs.pop_back();
if (l > r)
continue;
int mid = (l + r) >> 1;
pair<long long, int> best = {-1, -1};
for (int k = optr; k >= max(mid, optl); k--)
best = max(best, {C2(mid, k), k});
// debug(dp, best, ndp);
// debug(ans, best, mid);
ans = max(best.first, ans);
int opt = best.second;
dncs.push_back({mid + 1, r, opt, optr});
dncs.push_back({l, mid - 1, optl, opt});
}
// dncg(start + 1, n - 1, 0, start);
// dncs(0, start - 1, start, n - 1);
return ans;
}
int32_t main()
{
ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
int n, start, d;
cin >> n >> start >> d;
int attraction[n];
for (int i = 0; i < n; i++)
cin >> attraction[i];
cout << findMaxAttraction(n, start, d, attraction);
}