https://htoj.com.cn/cpp/oj/problem/detail?pid=22185117033728&tid=22487079604096&gid=22487067878400
#include <bits/stdc++.h>
#define ll long long
#define P 1000000007
using namespace std;
const int N = 200005;
int n, f[N][61], g[N][61], q;
ll dis[N], s, m, k;
char c[N];
int main(){cin >> n >> m >> q;cin >> c;int tmp = -1;for (int i =0; i < n; ++i)if (c[i] == '1') tmp = i;for (int i = n; i < 2 * n; ++i){if (c[i - n] == '1') tmp=i;if (tmp == -1) dis[i - n]= 0x3f3f3f3f3f3f3f3f;else dis[i - n] = i - tmp;}for (int i = 0; i < n; ++i){tmp=(i+m)%n;g[i][0]=max(m-dis[tmp],1ll)%P;f[i][0]=(i+max(m- dis[tmp],1ll))%n;}for (int j=1;j <= 60;++j)for (int i = 0; i < n; ++i){f[i][j] = f[f[i][j - 1]][j - 1];g[i][j] = (g[i][j - 1]+g[f[i][j - 1]][j -1]) % P;}while (q -- ){cin >> s >> k;ll ans = s % P;s=(s-1)%n;for(int j=0;j <= 60;++j)if ((k >> j) & 1){ans=(ans+g[s][j])% P;s=f[s][j];}cout << ans << "\n";}
}
