func_code_string: #include <bits/stdc++.h>   using namespace std;   int qread() {     char c;     int s = 0, f = 1;     while ((c = getchar()) <  0  || c >  9 ) (c ==  - ) && (f = -1);     do s = s * 10 + c -  0 ;     while ((c = getchar()) >=  0  && c <=  9 );     return s * f;   }   int n, m;   const int mod = 1e9 + 7;   int a[100011], pos[100011], bin[100011], inv[100011], sum[100011],       lp = 0, val[100011], vv[100011], svv[100011];   struct Ques {     int l, r, id;     bool operator<(const Ques &b) const { return r < b.r; }   } q[100011];   int ans[100011];   int WWW(long long v) { return v > 2000000001 ? 2000000001 : v; }   int main() {     n = qread();     m = qread();     bin[0] = inv[0] = 1;     for (int i = 1; i <= n; i++)       a[i] = qread(), bin[i] = (bin[i - 1] << 1) % mod,       inv[i] = 1ll * inv[i - 1] * ((mod + 1) >> 1) % mod,       sum[i] = ((sum[i - 1] + 1ll * a[i] * bin[i]) % mod + mod) % mod;     for (int i = 1; i <= m; i++) {       q[i].l = qread();       q[q[i].id = i].r = qread();     }     sort(q + 1, q + 1 + m);     pos[lp = 1] = 1;     int j = 1;     val[1] = a[1] * 2;     vv[1] = svv[1] = ((a[1] * 2) % mod + mod) % mod;     while (j <= m && q[j].r == 1) ans[q[j].id] = (a[1] + mod) % mod, j++;     for (int i = 2; i <= n; i++) {       if (a[i] <= 0)         pos[++lp] = i, val[lp] = 2 * a[i],         vv[lp] = (a[i] * 2ll % mod + mod) % mod,         svv[lp] = (svv[lp - 1] + vv[lp]) % mod;       else {         int cur =             WWW(0ll + val[lp] + bin[pos[lp] - pos[lp - 1] + 1] * 1ll * a[i]);         int cvv = (vv[lp] + bin[pos[lp] - pos[lp - 1] + 1] * 1ll * a[i]) % mod;         lp--;         while (lp && cur > 0) {           cur = WWW(0ll + val[lp] +                     (pos[lp] - pos[lp - 1] > 31 ? 2000000001                                                 : bin[pos[lp] - pos[lp - 1]]) *                         1ll * cur);           cvv = (vv[lp] + bin[pos[lp] - pos[lp - 1]] * 1ll * cvv) % mod;           lp--;         }         val[++lp] = cur;         pos[lp] = i;         vv[lp] = cvv;         svv[lp] = (svv[lp - 1] + vv[lp]) % mod;       }       while (j <= m && q[j].r == i) {         if (q[j].l == q[j].r) {           ans[q[j].id] = (a[i] + mod) % mod;           j++;           continue;         }         int l = q[j].l + 1, Ans = (a[q[j].l] + mod) % mod;         int L = 1, R = lp;         while (L < R) {           int mid = (L + R) >> 1;           if (pos[mid] >= l)             R = mid;           else             L = mid + 1;         }         Ans = (Ans + svv[lp] - svv[L]) % mod;         Ans = (Ans + mod) % mod;         Ans = (Ans + (sum[pos[L]] - sum[l - 1] + mod) * 1ll * inv[l - 1]) % mod;         ans[q[j].id] = Ans;         j++;       }     }     for (int i = 1; i <= m; i++) printf( %d n , ans[i]);     return 0;   }   