#include using namespace std; using VS = vector; using LL = long long; using VI = vector; using VVI = vector; using PII = pair; using PLL = pair; using VL = vector; using VVL = vector; #define ALL(a) begin((a)),end((a)) #define RALL(a) (a).rbegin(), (a).rend() #define PB push_back #define EB emplace_back #define MP make_pair #define SZ(a) int((a).size()) #define SORT(c) sort(ALL((c))) #define RSORT(c) sort(RALL((c))) #define UNIQ(c) (c).erase(unique(ALL((c))), end((c))) #define FOR(i, s, e) for (int(i) = (s); (i) < (e); (i)++) #define FORR(i, s, e) for (int(i) = (s); (i) > (e); (i)--) #define debug(x) cerr << #x << ": " << x << endl const int INF = 1e9; const LL LINF = 1e16; const LL MOD = 1000000007; const double PI = acos(-1.0); int DX[8] = { 0, 0, 1, -1, 1, 1, -1, -1 }; int DY[8] = { 1, -1, 0, 0, 1, -1, 1, -1 }; /* ----- 2018/05/01 Problem: yukicoder 127 / Link: http://yukicoder.me/problems/no/127 ----- */ /* ------問題------ 竹林とは、竹の長さを表す正の整数列 A1,A2…AN のことである。 門松もどきとは、1≤i1memo; //int memo[3000][3000][2]; VI a; //int a[3000]; int N; // [L,R] arrow -> int f(int L, int R, int arrow) { if (L < 0 || R >= N)return 0; if (memo[L][R][arrow] != -1)return memo[L][R][arrow]; int &ret = memo[L][R][arrow]; ret = 0; if (arrow) {// R-> if (R + 1 < N && a[L] > a[R + 1]) { ret = max(ret, f(L, R + 1, !arrow) + 1); } ret = max(ret, f(L, R + 1, arrow)); // not get } else {// <-L if (L - 1 >= 0 && a[L - 1] < a[R]) { ret = max(ret, f(L - 1, R, !arrow) + 1); } ret = max(ret, f(L - 1, R, arrow)); // not get } return ret; } int main() { cin.tie(0); ios_base::sync_with_stdio(false); cin >> N; a = VI(N); FOR(i, 0, N) { cin >> a[i]; } int ans = 0; memo = vector(N, VVI(N, VI(2, -1))); //fill(**memo, **memo + 3000 * 3000 * 2, -1); FOR(i, 0, N) { ans = max({ ans, f(i,i,0) + 1, f(i,i,1) + 1 }); } cout << ans << "\n"; return 0; }