【題解】Codeforces 1490G. Old Floppy Drive

#include <bits/stdc++.h>
using namespace std;
 
int cnt, t, n, m, a[200005];
long long pre[200005], mx, ans;
vector <long long> val, idx;
bool flag;
 
int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cin >> t;
    while (t--){
        cin >> n >> m;
        mx = 0;
        val.clear();
        idx.clear();
        val.push_back(0);
        idx.push_back(0);
        for (int i = 1; i <= n; i++){
            cin >> a[i];
            pre[i] = pre[i-1]+a[i];
            if (pre[i] > mx){
                mx = pre[i];
                val.push_back(pre[i]);
                idx.push_back(i);
            }
        }
        //if (a[1] == 16124 && a[2] == 8057) flag = true;
        for (int i = 0, q; i < m; i++){
            cin >> q;
            cnt++;
            //if (flag && cnt == 12701) cout << n << "_" << q << "_" << pre[n] << "_" << val.back() << " ";
            if (q > val.back() && pre[n] <= 0){
                cout << -1 << " ";
                continue;
            }
            else if (q <= val.back()){
                ans = idx[lower_bound(val.begin(), val.end(), q)-val.begin()];
                cout << ans-1 << " ";
                continue;
            }
            ans = (long long)n*((q-val.back()-1)/pre[n]+1);
            q -= ((q-val.back()-1)/pre[n]+1)*pre[n];
            ans += idx[lower_bound(val.begin(), val.end(), q)-val.begin()];
            cout << ans-1 << " ";
        }
        cout << "\n";
    }
}