Submission #942736

#	Time	Username	Problem	Language	Result	Execution time	Memory
942736		Pannda	Sum Zero (RMI20_sumzero)	C++17	61 / 100	310 ms	43448 KiB

sumzero

#include <bits/stdc++.h>
using namespace std;

struct DSU {
    vector<int> f;
    vector<int> depth;
    DSU(int n) : f(n), depth(n, 0) { iota(f.begin(), f.end(), 0); }

    void fix(int u) {
        if (f[u] == u) return;
        fix(f[u]);
        depth[u] += depth[f[u]];
        f[u] = f[f[u]];
    }

    void unionize(int u, int p) {
        f[u] = p;
        depth[u] = 1;
    }

    int getDepth(int u) {
        fix(u);
        return depth[u];
    }
};

int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);

    int n;
    cin >> n;

    auto [intervals, nxt, mp] = [&]() -> tuple<vector<pair<int, int>>, vector<int>, vector<vector<pair<int, int>>>> {
        vector<pair<long long, int>> a(n + 1);
        a[0] = {0, 0};
        for (int i = 0; i < n; i++) {
            int x;
            cin >> x;
            a[i + 1] = { a[i].first + x, i + 1 };
        }
        sort(a.begin(), a.end());
        vector<pair<int, int>> intervals;
        for (int i = 0; i < n; i++) {
            if (a[i].first == a[i + 1].first) {
                intervals.push_back({a[i].second, a[i + 1].second});
            }
        }
        vector<pair<long long, int>>().swap(a);
        sort(intervals.begin(), intervals.end(), [&](pair<int, int> x, pair<int, int> y) {
            return x.second < y.second;
        });
        vector<int> nxt(n + 1, -1);
        int last_l = -1, last_r = -1;
        for (int i = 0; i < intervals.size(); i++) {
            auto [l, r] = intervals[i];
            if (l <= last_l) continue;
            nxt[l] = i;
            last_l = l;
            last_r = r;
        }
        for (int i = n - 1; i >= 0; i--) {
            if (nxt[i] == -1) nxt[i] = nxt[i + 1];
        }
        vector<vector<pair<int, int>>> mp(n + 1);
        last_l = -1, last_r = -1;
        for (int i = 0; i < intervals.size(); i++) {
            auto [l, r] = intervals[i];
            if (l <= last_l) continue;
            if (nxt[r] != -1) {
                mp[intervals[nxt[r]].second].push_back({i, nxt[r]});
            }
            last_l = l;
            last_r = r;
        }
        return {intervals, nxt, mp};
    }();

    int q;
    cin >> q;
    vector<vector<pair<int, int>>> queries(n + 1);
    vector<int> ans(q, -1);
    for (int i = 0; i < q; i++) {
        int l, r;
        cin >> l >> r;
        l--;
        queries[r].push_back({l, i});
    }

    DSU dsu(intervals.size());
    for (int r = 0; r <= n; r++) {
        for (auto [u, p] : mp[r]) {
            dsu.unionize(u, p);
        }
        for (auto [l, i] : queries[r]) {
            int u = nxt[l];
            if (u == -1) ans[i] = 0;
            else ans[i] = intervals[u].second <= r ? dsu.getDepth(u) + 1 : 0;
        }
    }

    for (int i = 0; i < q; i++) {
        cout << ans[i] << '\n';
    }
}

Compilation message (stderr)

sumzero.cpp: In lambda function:
sumzero.cpp:55:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   55 |         for (int i = 0; i < intervals.size(); i++) {
      |                         ~~^~~~~~~~~~~~~~~~~~
sumzero.cpp:67:27: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   67 |         for (int i = 0; i < intervals.size(); i++) {
      |                         ~~^~~~~~~~~~~~~~~~~~
sumzero.cpp:54:26: warning: variable 'last_r' set but not used [-Wunused-but-set-variable]
   54 |         int last_l = -1, last_r = -1;
      |                          ^~~~~~

• Subtask 1: 22 / 22
• Subtask 2: 39 / 39
• Subtask 3: 0 / 39