Submission #956634

#	Time	Username	Problem	Language	Result	Execution time	Memory
956634		thinknoexit	Boat (APIO16_boat)	C++17	9 / 100	2 ms	492 KiB

boat

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
const int N = 505;
const ll MOD = 1e9 + 7;
int a[N], b[N];
ll qs[2 * N], dp[2 * N];
int main() {
    cin.tie(nullptr)->sync_with_stdio(false);
    int n;
    cin >> n;
    vector<int> c;
    c.push_back(0);
    for (int i = 1;i <= n;i++) {
        cin >> a[i] >> b[i];
        c.push_back(a[i] - 1);
        c.push_back(b[i]);
    }
    sort(c.begin(), c.end());
    c.resize(unique(c.begin(), c.end()) - c.begin());
    int m = c.size();
    for (int i = 0;i < m;i++) {
        qs[i] = 1;
    }
    for (int i = 1;i <= n;i++) {
        memset(dp, 0, sizeof dp);
        int l = lower_bound(c.begin(), c.end(), a[i] - 1) - c.begin();
        int r = lower_bound(c.begin(), c.end(), b[i]) - c.begin();
        for (int j = l + 1;j < m;j++) {
            if (j <= r) dp[j] = (dp[j - 1] + (qs[j - 1]) * (c[j] - c[j - 1]) % MOD) % MOD;
            else dp[j] = dp[j - 1];
        }
        for (int j = l + 1;j < m;j++) {
            qs[j] = (qs[j] + dp[j]) % MOD;
        }
    }
    cout << (qs[m - 1] - 1 + MOD) % MOD;
    return 0;
}

• Subtask 1: 9 / 9
• Subtask 2: 0 / 22
• Subtask 3: 0 / 27
• Subtask 4: 0 / 42