// Source: https://oj.uz/problem/view/IOI15_horses
//
#include "bits/stdc++.h"
using namespace std;
#define s second
#define f first
#define pb push_back
typedef long long ll;
typedef pair<ll, ll> pii;
typedef vector<pii> vpii;
typedef vector<ll> vi;
#define FOR(i, a, b) for (ll i = (a); i<b; i++)
bool ckmin(ll& a, ll b){ return b < a ? a = b, true : false; }
bool ckmax(ll& a, ll b){ return b > a ? a = b, true : false; }
const ll N = 5e5 + 10;
const ll MOD = 1e9 + 7;
#define lc i << 1
#define rc (i << 1) + 1
ll binpow(ll x, ll n) { // x ^ n
ll res = 1;
while (n > 0) {
if (n & 1) res = (res * x) % MOD;
x = (x * x) % MOD;
n/=2;
}
return res;
}
ll st[4 * N];
void up(ll i) {
st[i] = max(st[lc], st[rc]);
}
void update(ll ind, ll val, ll i = 1, ll l = 0, ll r = N) {
// cout << l << r << ' ' << st[i].lz << ' ' << val << endl;
// cout << l << r << st[i] << endl;
if (r == l) return;
if (r-1 == l && l == ind) {
st[i] = val;
return;
}
if (r-1 == l) return;
ll m = (l + r) / 2;
if (ind < m) update(ind, val, lc, l, m);
if (m <= ind) update(ind, val, rc, m, r);
up(i);
// cout << l << r << ' ' << st[i] << endl;
}
ll query(ll ql, ll qr, ll i = 1, ll l = 0, ll r = N) {
// cout << i << endl;
if (r == l) return 0;
if (ql <= l && r <= qr) {
// cout << ql << qr << ' ' << l << ' ' << r << ' ' << st[i] << endl;
return st[i];
}
if (r == l+1) return 0;
ll m = (l + r) / 2;
ll res = 0;
if (ql <= m) ckmax(res, query(ql, qr, lc, l, m));
if (qr >= m) ckmax(res, query(ql, qr, rc, m, r));
return res;
}
bool cmp(pii a, pii b) {
return (a.f * b.s < b.f * a.s);
}
set<ll> non = {-1};
vi fx, fy;
ll nn;
ll x_prod = 1;
ll solve() {
ll tot = 1;
pii frac = {0, 1};
auto it = prev(non.end(), 2);
for (; it != non.begin(); it--) {
// cout << *it << endl;
tot *= fy[*it];
if (tot > MOD) break;
ll rang = query(*it, *next(it, 1)+1);
// cout << rang << tot << endl;
pii here = {rang, tot};
if (cmp(frac, here)) {
frac=here;
}
// ckmax(mul, (binpow(tot, MOD-2) * rang % MOD));
}
ll mul = (frac.f * binpow(frac.s, MOD-2) % MOD);
// cout << mul << endl;
return x_prod * mul % MOD;
}
ll init(int n, int X[], int Y[]) {
nn = n;
non.insert(n + 1);
vi x(n), y(n);
x_prod = 1;
FOR(i, 0, n) {
x[i] = X[i];
y[i] = Y[i];
if (x[i] != 1) non.insert(i);
update(i, y[i]);
x_prod = (x_prod * x[i]) % MOD;
}
fx = x, fy = y;
// cout << query(0, 10) << endl;
// return 0;
return solve();
}
ll updateX(int pos, int val) {
x_prod = (x_prod * binpow(fx[pos], MOD-2)) % MOD;
if (fx[pos] != 1) non.erase(pos);
fx[pos]=val;
if (fx[pos] != 1) non.insert(pos);
x_prod = (x_prod * fx[pos]) % MOD;
return solve();
}
ll updateY(int pos, int val) {
fy[pos]=val;
update(pos, fy[pos]);
return solve();
}
// int main() {
// ios::sync_with_stdio(false);
// cin.tie(nullptr);
// cout << init(3, {2, 1, 3}, {3, 4, 1}) << endl;
// cout << updateY(1, 2) << endl;
// }
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
1 ms |
2396 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
0 ms |
2396 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
631 ms |
51668 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
1 ms |
2396 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |
# |
결과 |
실행 시간 |
메모리 |
Grader output |
1 |
Incorrect |
1 ms |
2392 KB |
Output isn't correct |
2 |
Halted |
0 ms |
0 KB |
- |