제출 #202582

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
202582		pr3pony	Boat (APIO16_boat)	C++14	9 / 100	14 ms	8444 KiB

boat

#include<bits/stdc++.h>
using namespace std;
const int N = 505, MOD = 1e9 + 7;
typedef long long ll;
vector<int> val;
typedef array<int, 2> ar;
ar p[N];
ll dp[N][2 * N], su[N][2 * N], inv[N];
int main()
{
    int n;
    cin >> n;
    val = {-1};
    for (int i = 1; i <= n; ++i) {
        cin >> p[i][0] >> p[i][1];
        ++p[i][1];
        val.push_back(p[i][0]);
        val.push_back(p[i][1]);
    }
    sort(val.begin(), val.end());
    val.resize(unique(val.begin(), val.end()) - val.begin());
    int w = val.size();

    inv[1] = 1;
    for (int i = 2; i <= n; ++i)
        inv[i] = (MOD - MOD / i) * inv[MOD % i] % MOD;

    dp[0][0] = 1;
    fill_n(su[0], w, 1);
    for (int b = 1; b <= n; ++b) {
        copy_n(dp[b - 1], w, dp[b]);
        for (int i = w - 1; i > 0; --i) {
            ll cn = val[i] - val[i - 1];
            ll cj = cn;
            for (int j = 1, o = b; j <= b && p[o][0] <= val[i - 1] && val[i] <= p[o][1]; ++j, --o) {
                //dp[b][i] += c(val[i] - val[i - 1], j) * su[o - 1][i - 1]
                (dp[b][i] += cj * su[o - 1][i - 1]) %= MOD;
                cj = cj * (cn - j) % MOD * inv[j + 1] % MOD;
            }
        }
        su[b][0] = dp[b][0];
        for (int i = 1; i < w; ++i)
            su[b][i] = (dp[b][i] + su[b][i - 1]) % MOD;
    }

    cout << (su[n][w - 1] + MOD - 1) % MOD << endl;
}

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