func_code_string: #include <bits/stdc++.h>   using namespace std;   const long long mod = 1e9 + 7;   const int N = 1e6 + 5;   int n, k, top;   int a[N], l[N], r[N], s[N];   long long ans;   long long calc(int l, int r) {     if (l > r || r - l + 1 < k) return 0;     int m = (r - l + 2 - k) / (k - 1);     long long ret = 1LL * (m + 1) * (r - l + 2 - k) % mod -                     1LL * (1 + m) * m / 2 % mod * (k - 1) % mod;     return ret;   }   int main() {     int i;     scanf( %d%d , &n, &k);     for (i = 1; i <= n; ++i) scanf( %d , &a[i]);     for (i = 1; i <= n; ++i) {       while (top && a[s[top]] < a[i]) --top;       l[i] = s[top] + 1, s[++top] = i;     }     top = 0, s[top] = n + 1;     for (i = n; i; --i) {       while (top && a[s[top]] <= a[i]) --top;       r[i] = s[top] - 1, s[++top] = i;     }     for (i = 1; i <= n; ++i)       ans = (ans +              (calc(l[i], r[i]) - calc(l[i], i - 1) - calc(i + 1, r[i])) * a[i]) %             mod;     if (ans < 0) ans += mod;     printf( %lld n , ans);     return 0;   }   