This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
// 石室詩士施氏, 嗜獅, 誓食十獅。
// 氏時時適市視獅。
// 十時, 適十獅適市。
// 是時, 適施氏適市。
// 氏視是十獅, 恃矢勢, 使是十獅逝世。
// 氏拾是十獅屍, 適石室。
// 石室濕, 氏使侍拭石室。
// 石室拭, 氏始試食是十獅。
// 食時, 始識是十獅, 實十石獅屍。
// 試釋是事。
#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define pii pair<int,int>
#define pb push_back
#define ppb pop_back
#define mp make_pair
#define f first
#define se second
template <typename T> void Max(T &a, T b) {
	a = max(a, b);
}
template <typename T> void Min(T &a, T b) {
	a = min(a, b);
}
const int inf = 0x3f3f3f3f;
const int N = 4e5 + 15;
int n, q, p[N], to[N];
map <int, int> last;
vector <int> g[N], st;
vector <pii> qs[N];
int ans[N], d[N], l, r, mid;
void dfs(int v) {
	st.pb(v);
	for(pii &e : qs[v]) {
		l = 0, r = (int)st.size() - 1;
		while(l <= r) {
			mid = l + r >> 1;
			if(st[mid] <= e.f)
				r = mid - 1, Max(ans[e.se], d[v] - d[st[mid]]);
			else
				l = mid + 1;
		}
	}
	for(int to : g[v]) {
		d[to] = d[v] + 1;
		dfs(to);
	}
	st.ppb();
}
int main() {
	ios_base::sync_with_stdio(0), cout.tie(0), cin.tie(0);
	// freopen("input.txt", "r", stdin);
	cin >> n;
	for(int i = 1; i <= n; ++i) {
		cin >> p[i];
		p[i] += p[i-1];
	}
	for(int i = 0; i <= n + 1; ++i)
		to[i] = n + 1;
	for(int i = n; i >= 0; --i) {
		if(last.count(p[i]))
			Min(to[i], last[p[i]]);
		Min(to[i], to[i+1]);
		g[to[i]].pb(i);
		last[p[i]] = i;
	}
	cin >> q;
	for(int i = 1; i <= q; ++i) {
		int l, r;
		cin >> l >> r;
		qs[l - 1].pb({r, i});
	}
	dfs(n + 1);
	for(int i = 1; i <= q; ++i)
		cout << ans[i] << endl;
	return 0;
}
Compilation message (stderr)
sumzero.cpp: In function 'void dfs(int)':
sumzero.cpp:44:12: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   44 |    mid = l + r >> 1;
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