这个缩进看得我难受，自己对着写了遍，测试样例都没过，楼主看看哪里错了。 typedef long long LL; int main() {     int n;     cin >> n;     if (n <= 1)     {         cout << 0 << endl;         return 0;     }     vector<LL> a(n);     for (int i = 0; i < n; i++)         cin >> a[i];     stack<pair<LL, int> > s;     vector<int> c(n), d(n);     for (int i = 0; i < n; i++)     {         while (!s.empty() && s.top().first > a[i])             s.pop();         if (s.empty())             c[i] = -1;         else             c[i] = s.top().second;         s.push(make_pair(a[i], i));     }     s = stack<pair<LL, int> >();     for (int i = n - 1; i >= 0; i--)     {         while (!s.empty() && s.top().first >= a[i])             s.pop();         if (s.empty())             d[i] = n;         else             d[i] = s.top().second;         s.push({ a[i], i });     }     LL res = 0;     for (int i = 0; i < n; i++)     {         res -= a[i] * (i - c[i]) * (d[i] - i);     }     s = stack<pair<LL, int> >();     for (int i = 0; i < n; i++)     {         while (!s.empty() && s.top().first <= a[i])             s.pop();         if (s.empty())             c[i] = -1;         else             c[i] = s.top().second;         s.push({ a[i], i });     }     s = stack<pair<LL, int> >();     for (int i = n - 1; i >= 0; i--)     {         while (!s.empty() && s.top().first < a[i])             s.pop();         if (s.empty())             d[i] = n;         else             d[i] = s.top().second;         s.push({ a[i], i });     }     for (int i = 0; i < n; i++)     {         res += a[i] * (i - c[i]) * (d[i] - 1);     }     cout << res << endl;     return 0; }