func_code_string: #include <bits/stdc++.h>   using namespace std;   template <typename T, class F = function<T(const T&, const T&)>>   class SparseTable {    public:     int n;     vector<vector<T>> sp;     F func;     SparseTable(const vector<T>& a, const F& f) : func(f) {       n = static_cast<int>(a.size());       int max_log = 32 - __builtin_clz(n);       sp.resize(max_log);       sp[0] = a;       for (int j = 1; j < max_log; ++j) {         sp[j].resize(n - (1 << j) + 1);         for (int i = 0; i <= n - (1 << j); ++i) {           sp[j][i] = func(sp[j - 1][i], sp[j - 1][i + (1 << (j - 1))]);         }       }     }     T get(int l, int r) const {       int lg = 32 - __builtin_clz(r - l + 1) - 1;       return func(sp[lg][l], sp[lg][r - (1 << lg) + 1]);     }   };   int main() {     ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);     int n;     cin >> n;     vector<int> a(n + 1), nxt(n + 1), prv(n + 1), cum(n + 1);     for (int i = 1; i <= n; i++) {       cin >> a[i];       cum[i] = cum[i - 1] + a[i];     }     for (int i = n; i >= 1; i--) {       nxt[i] = i + 1;       while (nxt[i] <= n && a[nxt[i]] <= a[i]) nxt[i] = nxt[nxt[i]];     }     for (int i = 1; i <= n; i++) {       prv[i] = i - 1;       while (prv[i] >= 1 && a[prv[i]] <= a[i]) prv[i] = prv[prv[i]];     }     SparseTable<int> mn_sp(cum, [&](int i, int j) { return min(i, j); });     SparseTable<int> mx_sp(cum, [&](int i, int j) { return max(i, j); });     int ans = 0;     for (int i = 1; i <= n; i++) {       int l = prv[i] + 1, r = nxt[i] - 1;       ans = max(ans, mx_sp.get(i, r) - mn_sp.get(l - 1, i - 1) - a[i]);     }     cout << ans;   }   