#include <bits/stdc++.h>
using namespace std;
#define fast ios::sync_with_stdio(NULL); cin.tie(0); cout.tie(0);
#define MAXN 200011
#define SQRSIZE 500
int arr[MAXN];
int block[SQRSIZE];
int n, blk_sz, pp = 1;
string s;
int query(int l, int r)
{
int sum = 0;
int idx = n - r;
int p = 1;
while (l < r && idx % blk_sz != 0)
{
sum = (sum + arr[r] * p) % 10;
r--;
idx++;
p = (p * 2) % 10;
}
while (l + blk_sz - 1 <= r)
{
sum = (sum + block[idx / blk_sz] * p) % 10;
p = (p * pp) % 10;
r -= blk_sz;
idx += blk_sz;
}
while (l<=r)
{
sum = (sum + arr[r] * p) % 10;
p = (p * 2) % 10;
r--;
}
return sum;
}
void preprocess()
{
int blk_idx = -1;
blk_sz = sqrt(n);
int p = 1;
for(int i = n, j = 0; i > 0; i--, j++)
{
arr[i] = s[i] - '0';
if (j % blk_sz == 0)
{
p = 1;
blk_idx++;
}
block[blk_idx] += (arr[i] * p) % 10;
p = (p * 2) % 10;
}
}
int q, l, r;
int main()
{
fast
cin >> s;
n = s.size();
s = " " + s;
preprocess();
for(int i = 0; i < blk_sz; i++) pp = (pp * 2) % 10;
cin >> q;
while(q--)
{
cin >> l >> r;
cout << query(l, r) << endl;
}
}
Copy