| # | Time | Username | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 1344289 | MunkhErdene | The Big Prize (IOI17_prize) | C++17 | 0 ms | 0 KiB |
#include "prize.h"
#include<bits/stdc++.h>
using namespace std;
#define ll long long
#define pb push_back
#define ff first
#define ss second
#define _ << " " <<
#define yes cout<<"YES\n"
#define no cout<<"NO\n"
#define ull unsigned long long
#define lll __int128
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()
#define BlueCrowner ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
#define FOR(i, a, b) for (ll i = (a); i < (b); i++)
#define FORD(i, a, b) for (ll i = (a); i >= (b); i--)
const ll NAIM = 1e18;
static const int max_q = 10000;
static int n;
static int query_count = 0;
static vector<int> g;
static vector<vector<int> > rank_count;
vector<int> ask(int i) {
query_count++;
if(query_count > max_q) {
cerr << "Query limit exceeded" << endl;
exit(0);
}
if(i < 0 || i >= n) {
cerr << "Bad index: " << i << endl;
exit(0);
}
vector<int> res(2);
res[0] = rank_count[g[i] - 1][i + 1];
res[1] = rank_count[g[i] - 1][n] - res[0];
return res;
}
int find_best(int n) {
ll cur = 0;
FOR(i, 0, min(474, n)) {
vector<int> a = ask(i);
if(a[0] + a[1] > cur) {
cur = a[0] + a[1];
}
}
ll L = 0;
ll mn = NAIM, pos;
while(mn){
ll l = L, r = n - 1;
ll p = n - 1;
while(l <= r) {
ll m = (l + r) >> 1;
vector<int> a = ask(m);
if(a[0] + a[1] < mn) {
mn = a[0] + a[1];
pos = m;
}
if(a[1] < cur) {
p = m;
r = m - 1;
}
else l = m + 1;
}
L = p + 1;
};
return pos;
}
int main() {
cin >> n;
g.resize(n);
for(int i = 0; i < n; i++) {
cin >> g[i];
if(g[i] < 1) {
cerr << "Invalid rank " << g[i] << " at index " << i << endl;
exit(0);
}
}
int max_rank = *max_element(g.begin(), g.end());
rank_count.resize(max_rank + 1, vector<int>(n + 1, 0));
for(int r = 0; r <= max_rank; r++) {
for(int i = 1; i <= n; i++) {
rank_count[r][i] = rank_count[r][i - 1];
if(g[i - 1] == r)
rank_count[r][i]++;
}
}
for(int i = 0; i <= n; i++)
for(int r = 1; r <= max_rank; r++)
rank_count[r][i] += rank_count[r - 1][i];
int res = find_best(n);
cout << res << endl << "Query count: " << query_count << endl;
return 0;
}