#include <algorithm>
#include <iostream>
#include <vector>
using namespace std;
int main()
{
ios::sync_with_stdio(false);
cin.tie(nullptr);
int n;
cin >> n;
vector<int> a(2 * n);
for (int i = 0; i < n; ++i)
{
cin >> a[i];
a[i + n] = a[i];
}
vector<int> next(2 * n);
vector<int> prev(2 * n);
int curInd = n;
int curMax = a[n];
int res = 1;
if (n > 1)
{
for (int i = n + 1; i < 2 * n; ++i)
{
if (a[i] > curMax)
{
prev[i] = curInd;
next[curInd] = i;
curInd = i;
curMax = a[i];
++res;
}
}
int tmp = res;
for (int i = n - 1; i >= 1; --i)
{
if (prev[i + n] > 0)
{
next[prev[i + n]] = 0;
prev[i + n] = 0;
--tmp;
}
curInd = i + 1;
while (a[i] >= a[curInd])
{
--tmp;
if (next[curInd] == 0)
break;
curInd = next[curInd];
next[prev[curInd]] = 0;
prev[curInd] = 0;
}
if (a[i] < a[curInd])
{
next[i] = curInd;
prev[curInd] = i;
}
++tmp;
res = max(res, tmp);
}
}
cout << res << "\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 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 | #include <algorithm> #include <iostream> #include <vector> using namespace std; int main() { ios::sync_with_stdio(false); cin.tie(nullptr); int n; cin >> n; vector<int> a(2 * n); for (int i = 0; i < n; ++i) { cin >> a[i]; a[i + n] = a[i]; } vector<int> next(2 * n); vector<int> prev(2 * n); int curInd = n; int curMax = a[n]; int res = 1; if (n > 1) { for (int i = n + 1; i < 2 * n; ++i) { if (a[i] > curMax) { prev[i] = curInd; next[curInd] = i; curInd = i; curMax = a[i]; ++res; } } int tmp = res; for (int i = n - 1; i >= 1; --i) { if (prev[i + n] > 0) { next[prev[i + n]] = 0; prev[i + n] = 0; --tmp; } curInd = i + 1; while (a[i] >= a[curInd]) { --tmp; if (next[curInd] == 0) break; curInd = next[curInd]; next[prev[curInd]] = 0; prev[curInd] = 0; } if (a[i] < a[curInd]) { next[i] = curInd; prev[curInd] = i; } ++tmp; res = max(res, tmp); } } cout << res << "\n"; return 0; } |
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