#include <bits/stdc++.h>
using namespace std;
int main(){
//magiczne linie prędkości
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n;
cin >> n;
vector<int> a(n);
for (int i = 0; i < n; i++){
cin >> a[i];
}
vector<int> doubled(2 * n);
for (int i = 0; i < 2 * n; i++){
doubled[i] = a[i % n];
}
vector<int> prev_geq(2 * n, -1);
stack<int> stk;
for (int i = 0; i < 2 * n; i++){
while (!stk.empty() && doubled[stk.top()] < doubled[i]){
stk.pop();
}
prev_geq[i] = stk.empty() ? -1 : stk.top();
stk.push(i);
}
vector<int> diff(n + 1, 0);
for (int i = 0; i < 2 * n; i++){
int left = prev_geq[i] + 1;
int right = i;
left = max(left, 0);
right = min(right, n - 1);
if (left <= right) {
diff[left]++;
if (right + 1 <= n) diff[right + 1]--;
}
}
int ans = 0, sum = 0;
for (int i = 0; i < n; i++){
sum += diff[i];
ans = max(ans, sum);
}
cout << ans << "\n";
return 0;
}
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 | #include <bits/stdc++.h> using namespace std; int main(){ //magiczne linie prędkości ios_base::sync_with_stdio(false); cin.tie(NULL); int n; cin >> n; vector<int> a(n); for (int i = 0; i < n; i++){ cin >> a[i]; } vector<int> doubled(2 * n); for (int i = 0; i < 2 * n; i++){ doubled[i] = a[i % n]; } vector<int> prev_geq(2 * n, -1); stack<int> stk; for (int i = 0; i < 2 * n; i++){ while (!stk.empty() && doubled[stk.top()] < doubled[i]){ stk.pop(); } prev_geq[i] = stk.empty() ? -1 : stk.top(); stk.push(i); } vector<int> diff(n + 1, 0); for (int i = 0; i < 2 * n; i++){ int left = prev_geq[i] + 1; int right = i; left = max(left, 0); right = min(right, n - 1); if (left <= right) { diff[left]++; if (right + 1 <= n) diff[right + 1]--; } } int ans = 0, sum = 0; for (int i = 0; i < n; i++){ sum += diff[i]; ans = max(ans, sum); } cout << ans << "\n"; return 0; } |
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