Submission #1027553

#	Time	Username	Problem	Language	Result	Execution time	Memory
1027553		stdfloat	Boat (APIO16_boat)	C++17	31 / 100	2063 ms	524116 KiB

boat

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

using ll = long long;

const int md = (int)1e9 + 7;

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

    int n;
    cin >> n;

    vector<int> a(n), b(n);
    for (int i = 0; i < n; i++) cin >> a[i] >> b[i];

    map<int, int> m;
    for (int i = 0; i < n; i++) {
        for (int j = a[i]; j <= b[i]; j++) m[j] = 1;
    }

    int x = 0;
    for (auto &i : m) i.second = ++x;

    vector<int> fn(x + 1), dp(x + 1);
    for (int i = 0; i < n; i++) {
        int sm = 0;
        for (int j = m[b[i]]; j > 0; j -= j & -j) sm = (sm + fn[j]) % md;

        // cout << "\ni " << i << ' ' << sm << '\n';

        for (int j = m[b[i]]; j >= m[a[i]]; j--) {
            sm = ((sm - dp[j]) % md + md) % md;
            dp[j] = (dp[j] + sm + 1) % md;
            
            // cout << "j " << j << ' ' << sm + 1 << '\n';

            for (int k = j; k <= x; k += k & -k) fn[k] = (fn[k] + sm + 1) % md;
            // for (int k = 1; k < j; k++) dp[j] = (dp[j] + dp[k]) % md;
        }
    }

    int sm = 0;
    for (auto i : dp) sm = (sm + i) % md;

    cout << sm << '\n';
}

/*sub1
vector<int> dp(n);
for (int i = 0; i < n; i++) {
    dp[i] = 1;
    for (int j = 0; j < i; j++) {
        if (a[j] < a[i]) dp[i] = (dp[i] + dp[j]) % md;
    }
}

int sm = 0;
for (auto i : dp) sm = (sm + i) % md;

cout << sm;
*/

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