Submission #657128

#	Time	Username	Problem	Language	Result	Execution time	Memory
657128		benjaminkleyn	Examination (JOI19_examination)	C++17	0 / 100	3074 ms	48136 KiB

examination

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

int n, q;
vector<pair<ll,ll>> block[1001][1001];
ll suff[1001][1001];

ll query(ll A, ll B, ll C)
{
    ll res = 0;
    for (int i = A / 1000; i <= 1000; i++)
    {
        // for each value i, the a-value is in the range
        // i * 1000 <= x <= (i + 1) * 1000 - 1
        // we want to find the first j such that 
        // j * 1000 >= B and (i + j) * 1000 >= C
        // then add the suffix sum block[i][j] + block[i][j+1] + ... + block[i][1000].
        int j = max((B + 999) / 1000, (C + 999) / 1000 - i);
        res += suff[i][j];
        for (int k = min(B / 1000, C / 1000 - i); k < j; k++)
            for (auto [a, b] : block[i][k])
                if (a + b >= C && a >= A && b >= B)
                    res++;
    }
    return res;
}

int main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);

    cin >> n >> q;
    for (int i = 0; i < n; i++)
    {
        ll a, b;
        cin >> a >> b;
        block[a  / 1000][b / 1000].push_back({a, b});
    }
    for (int i = 0; i <= 1000; i++)
    {
        suff[i][1000] = block[i][1000].size();
        for (int j = 999; j >= 0; j--)
            suff[i][j] = suff[i][j+1] + block[i][j].size(); 
    }

    ll A, B, C;
    while (q--)
    {
        cin >> A >> B >> C;
        cout << query(A, B, C) << '\n';
    }

    return 0;
}

• Subtask 1: 0 / 2
• Subtask 2: 0 / 20
• Subtask 3: 0 / 21
• Subtask 4: 0 / 57