// compile: make data // run: ./data < data.in #include <bits/stdc++.h> using namespace std; #pragma GCC optimize("O3,unroll-loops") #pragma GCC target("avx2,bmi,bmi2,lzcnt,popcnt") #ifdef LOCAL #include <debug/codeforces.h> #define debug(x...) _debug_print(#x, x); #define Debug(x...) _debug_print_format(#x, x); std::ifstream terminal("/dev/tty"); #define PP cerr<<"\033[1;30mpause...\e[0m",terminal.ignore(); #else #define debug(x...) #define Debug(x...) #define PP #endif template<typename...Args> void print_(Args...args){((cout<<args<<" "),...)<<endl;} #define rep(i,a,b) for(int i=(a);i<(int)(b);++i) #define sz(v) ((int)(v).size()) #define print(...) print_(__VA_ARGS__); #define FIND(a, x) ((find(a.begin(),a.end(),(x))!=a.end())?1:0) #define cmin(x,...) x=min({(x),__VA_ARGS__}) #define cmax(x,...) x=max({(x),__VA_ARGS__}) #define INTMAX (int)(9223372036854775807) #define INF (int)(1152921504606846976) #define NaN (int)(0x8b88e1d0595d51d1) #define double long double #define int long long #define uint unsigned long long #define MAXN 200010 struct stmin { vector<int> a, lg; vector<vector<int>> dp; stmin(vector<int> v) { a = v; build(); } void build() { int logn = log2(sz(a)) + 2; dp.assign(sz(a), vector<int>(logn, 0)); rep(i, 0, sz(a)) dp[i][0] = a[i]; rep(j, 1, logn) { rep(i, 0, sz(a)) { dp[i][j] = min(dp[i][j-1], dp[min(i + (1 << (j-1)), sz(a)-1)][j-1]); } } lg.resize(sz(a)+1); lg[1] = 0; rep(i, 2, sz(a)+1) lg[i] = lg[i/2] + 1; } int query(int l, int r) { int j = lg[r - l + 1]; return min(dp[l][j], dp[r - (1 << j) + 1][j]); } }; int32_t main() { ios::sync_with_stdio(false); cin.tie(nullptr); cout.tie(nullptr); int n; cin >> n; vector<int> a(n); rep(i, 0, n) cin >> a[i]; stmin st(a); function<int(int, int)> cdq = [&](int l, int r) { if (l == r) return a[l]; int mid = (l + r) / 2; int lc = cdq(l, mid), rc = cdq(mid+1, r); set<int, greater<int>> s; rep(i, l, r+1) if (a[i] <= min(a[mid], a[mid+1])) s.insert(a[i]); int i = mid, j = mid+1, height = min(a[mid], a[mid+1]), cur = 2 * height; for (auto it = s.begin(); it != s.end(); ++it) { while (i-1 >= l && a[i-1] >= *it) --i, cmin(height, a[i]); while (j+1 <= r && a[j+1] >= *it) ++j, cmin(height, a[j]); cmax(cur, (j - i + 1) * height); } return max({lc, rc, cur}); }; int ans = cdq(0, n-1); cout << ans << endl; return 0; }
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