#include <iostream>
#include <vector>
#include <algorithm>
#include <stack>
using namespace std;
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
int n;
if (!(cin >> n)) return 0;
vector<int> a(n);
int max_val = -1;
for (int i = 0; i < n; ++i) {
cin >> a[i];
if (a[i] > max_val) max_val = a[i];
}
vector<int> b(2 * n);
for (int i = 0; i < n; ++i) {
b[i] = b[i + n] = a[i];
}
vector<int> next_greater(2 * n, -1);
stack<int> s;
for (int i = 2 * n - 1; i >= 0; --i) {
while (!s.empty() && b[s.top()] <= b[i]) {
s.pop();
}
if (!s.empty()) {
next_greater[i] = s.top();
}
s.push(i);
}
vector<int> dp(2 * n, 0);
for (int i = 2 * n - 1; i >= 0; --i) {
if (b[i] == max_val) {
dp[i] = 1;
} else if (next_greater[i] != -1 && next_greater[i] < i + n) {
dp[i] = 1 + dp[next_greater[i]];
} else {
dp[i] = 1;
}
}
int result = 0;
for (int i = 0; i < n; ++i) {
result = max(result, dp[i]);
}
cout << result << endl;
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 55 56 57 58 | #include <iostream> #include <vector> #include <algorithm> #include <stack> using namespace std; int main() { ios_base::sync_with_stdio(false); cin.tie(NULL); int n; if (!(cin >> n)) return 0; vector<int> a(n); int max_val = -1; for (int i = 0; i < n; ++i) { cin >> a[i]; if (a[i] > max_val) max_val = a[i]; } vector<int> b(2 * n); for (int i = 0; i < n; ++i) { b[i] = b[i + n] = a[i]; } vector<int> next_greater(2 * n, -1); stack<int> s; for (int i = 2 * n - 1; i >= 0; --i) { while (!s.empty() && b[s.top()] <= b[i]) { s.pop(); } if (!s.empty()) { next_greater[i] = s.top(); } s.push(i); } vector<int> dp(2 * n, 0); for (int i = 2 * n - 1; i >= 0; --i) { if (b[i] == max_val) { dp[i] = 1; } else if (next_greater[i] != -1 && next_greater[i] < i + n) { dp[i] = 1 + dp[next_greater[i]]; } else { dp[i] = 1; } } int result = 0; for (int i = 0; i < n; ++i) { result = max(result, dp[i]); } cout << result << endl; return 0; } |
English