| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 317558 | Kevin_Zhang_TW | Hidden Sequence (info1cup18_hidden) | 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.
#pragma GCC optimize("Ofast")
#include<bits/stdc++.h>
#define pb emplace_back
#define AI(i) begin(i), end(i)
using namespace std;
using ll = long long;
#ifdef KEV
#define DE(args...) kout("[ " + string(#args) + " ] : ", args)
void kout() { cerr << endl; }
template<class T, class ...U>
void kout(T a, U ...b) { cerr << a << ' ', kout(b...); }
void debug(auto L, auto R) { while (L != R) cerr << *L << " \n"[next(L) == R], ++L; }
vector<int> ans{0,1,0,0,0,0,0,0,0,1,1};
int mxq;
bool isSubsequence(vector<int> a) {
for (int i = 0, j = 0;i < a.size();++i) {
while (j < ans.size() && ans[j] != a[i])
++j;
if (j == ans.size()) return false;
++j;
}
mxq = max(mxq, (int)a.size());
return true;
}
#else
#include "grader.h"
#define debug(...) 0
#define DE(...) 0
#endif
const int MAX_N = 300010, inf = 1e9;
int n;
bool query(vector<int> a) {
if (a.size() > n) return false;
return isSubsequence(a);
}
vector<int> operator + (vector<int> a, const vector<int> &b) {
a.insert(end(a), AI(b));
return a;
}
vector<pair<int,int>> edge[MAX_N];
int dp[MAX_N];
vector<int> findSequence(int _n) {
n = _n;
int flip = 0;
auto makev = [&](int a, int v1, int b, int v2, int c, int v3) {
vector<int> res(a+b+c);
for (int i = 0;i < a;++i)
res[i] = v1^flip;
for (int i = a;i < a+b;++i)
res[i] = v2^flip;
for (int i = a+b;i < a+b+c;++i)
res[i] = v3^flip;
return res;
};
auto con = [&](int l, int r, int sum) {
DE(l, r, sum);
edge[r].pb(l-1, -sum);
};
auto concon = [&](int l, int r, int sum) {
edge[l-1].pb(r, sum);
};
DE(n);
vector<int> Z, O, ans;
while (Z.size() == O.size() && Z.size() + O.size() < n) {
if (query(Z + zero))
Z.pb(0);
if (query(O + one))
O.pb(1);
}
if (Z.size() > O.size())
swap(Z, O), flip ^= 1;
while (Z.size () + O.size () < n)
O.pb(0);
int m = Z.size();
//con(1, m+1, O.size());
auto bellmand = [&]() {
dp[m+1] = O.size();
fill(dp+1, dp+m+1, inf);
queue<int> q;
vector<bool> inq(m+2);
auto mpush = [&](int x) {
if (inq[x]) return;
inq[x] = true;
q.emplace(x);
};
mpush(0), mpush(m+1);
while (q.size()) {
int x = q.front(); q.pop();
inq[x] = false;
for (auto [u, w] : edge[x])
if (dp[x] + w < dp[u]) {
dp[u] = dp[x] + w;
mpush(u);
}
}
};
//const int lim = (n * 3 + 3) / 4;
const int lim = ((n) / 2) + 1;
for (int l0 = 0 ; l0 <= m ; ++l0)
for (int r0 = 0 ; r0 + l0 <= m ; ++r0) {
int mx1 = 0;
int l = 0, r = lim - l0 - r0, mid;
while (l < r) {
mid = l + r >> 1;
if (query(makev(l0, 0, mid+1, 1, r0, 0)))
l = mid+1;
else
r = mid;
}
mx1 = l;
DE(mx1);
//assert(query(makev(l0, 0, l, 1, r0, 0)));
con(l0+1, m+1 - r0, mx1);
if (l0 + r0 + mx1 < lim)
concon(l0+1, m+1 - r0, mx1);
}
bellmand();
for (int i = m+1;i >= 1;--i)
dp[i] -= dp[i-1];
for (int i = 1;i <= m+1;++i) {
while (dp[i]--)
ans.pb( 1 ^ flip );
if (i <= m)
ans.pb( 0 ^ flip );
}
return ans;
}
#ifdef KEV
int32_t main() {
ios_base::sync_with_stdio(0), cin.tie(0);
vector<int> res = findSequence(ans.size());
if (res == ans) {
cerr << "AC!\n";
DE(mxq);
}
else {
cerr << "WA\n";
debug(AI(res));
cerr << "Should be\n";
debug(AI(ans));
}
}
#endif