func_code_string: #include <bits/stdc++.h>   using namespace std;   int n, a[300005], pre[300005], L[300005], R[300005];   int st[300005][19], f[300005], ans;   int Max(int l, int r) {     int s = f[r - l];     return a[st[l][s]] > a[st[r - (1 << s)][s]] ? st[l][s] : st[r - (1 << s)][s];   }   void solve(int l, int r) {     if (l > r) return;     if (l == r) {       ans += a[l] == 1;       return;     }     int k = Max(l, r);     if (k - l < r - k) {       for (int i = l; i <= k; i++)         if (i + a[k] - 1 >= k && i + a[k] - 1 <= r && R[i] >= i + a[k] - 1) ans++;     } else       for (int i = k; i <= r; i++)         if (i - a[k] + 1 <= k && i - a[k] + 1 >= l && L[i] <= i - a[k] + 1) ans++;     solve(l, k - 1), solve(k + 1, r);   }   int main() {     scanf( %d , &n);     for (int i = 2; i <= n; i++) f[i] = f[i >> 1] + 1;     for (int i = 1; i <= n; i++) scanf( %d , &a[i]);     for (int i = 1; i < n; i++) st[i][0] = a[i] > a[i + 1] ? i : (i + 1);     for (int i = 1; i <= n; i++)       L[i] = max(L[i - 1], pre[a[i]] + 1), pre[a[i]] = i;     for (int i = 1; i <= n; i++) pre[i] = n + 1;     R[n] = n, pre[a[n]] = n;     for (int i = n - 1; i >= 1; i--)       R[i] = min(R[i + 1], pre[a[i]] - 1), pre[a[i]] = i;     for (int i = 1; 1 << i < n; i++)       for (int j = 1; j <= n - (1 << i); j++)         st[j][i] = a[st[j][i - 1]] > a[st[j + (1 << i - 1)][i - 1]]                        ? st[j][i - 1]                        : st[j + (1 << i - 1)][i - 1];     solve(1, n);     printf( %d n , ans);     return 0;   }   