| # | Submission time | Handle | Problem | Language | Result | Execution time | Memory |
|---|---|---|---|---|---|---|---|
| 874843 | 2023-11-17T23:41:33 Z | Matjaz | Teams (CEOI11_tea) | C++14 | 0 ms | 0 KB |
#include <vector>
#include <algorithm>
#include <iostream>
using namespace std;
// Insight: each S[i] E[i] corresponds to some interval in the original set of positions
// The interval only matters if your player is in it - and there is a unique answer as to whether it wins or loses
// You can find the best position with a sweep.
// Does linked list + fenwick tree work?
vector<int> tree;
int N;
int sum(int x){
int s = 0;
x++;
while (x > 0){
s += tree[x];
x -= x & (-x);
}
return s;
}
int find(int x){
int l = 0;
int u = N - 1;
while (l < u){
int mid = l + (u - l) / 2;
//cout << mid << " " << sum(mid) << endl;
if (sum(mid) < x) l = mid + 1; else u = mid;
}
return l;
}
void update(int x,int v){
x++;
while (x <= tree.size()){
tree[x] += v;
x += x & (-x);
}
}
int GetBestPosition(int _N, int C, int R, int *K, int *S, int *E) {
N = _N;
vector<int> s(N+1);
s[0] = 0;
for (int i=1;i<=N;i++) s[i] = s[i-1] + (K[i-1] > R);
vector<int> next(N);
for (int i=0;i<N;i++) next[i] = i + 1;
vector<pair<int,int> > sweep_events;
tree.assign(N + 2, 0);
for (int i=0;i<N;i++) update(i, 1);
for (int i=0;i<C;i++){
int left = find(S[i] + 1);
int right = find(E[i] + 1);
//We can put in assert(left is active)
int tmp = left;
while (tmp != right){
tmp = next[tmp];
update(tmp, -1);
}
next[left] = next[right];
right = next[left] - 1;
//cout << S[i] << " " << E[i] << " " << left << " " << right << endl;
if (s[right] - s[left] == 0){
sweep_events.push_back(make_pair(left, 1));
sweep_events.push_back(make_pair(right + 1, -1));
}
}
sort(sweep_events.begin(), sweep_events.end());
int best_position = 0;
int best_wins = 0;
int wins = 0;
for (int i=0;i<sweep_events.size();i++){
wins += sweep_events[i].second;
if (wins > best_wins){
best_wins = wins;
best_position = sweep_events[i].first;
}
}
return best_position;
}