Submission #1118533

#	Time	Username	Problem	Language	Result	Execution time	Memory
1118533		lmToT27	Boat (APIO16_boat)	C++17	100 / 100	593 ms	8424 KiB

boat

#include <bits/stdc++.h>
#define all(dataStructure) dataStructure.begin(),dataStructure.end()

using namespace std;

typedef long long ll;

const int MAX = 5e2 + 3;
const ll MOD[] = {1000000007, 998244353};
const ll mod = 1e9 + 7;

int n, l[MAX], r[MAX];
ll dp[MAX][2 * MAX], C[MAX][2 * MAX];

template <typename dataType>
inline void compress(vector <dataType> &x) {
        sort(all(x));
        x.erase(unique(all(x)), x.end());
}

ll pw(ll a, ll b) {
        ll res = 1;
        for (; b > 0; b >>= 1) {
                if (b & 1) res = res * a % mod;
                a = a * a % mod;
        }
        return res;
}

void Solve() {
        vector <int> val;
        cin >> n;
        for (int i = 1; i <= n; i++) {
                cin >> l[i] >> r[i];
                l[i]--;
                val.push_back(l[i]);
                val.push_back(r[i]);
        }

        compress(val);

        for (int i = 1; i < (int)val.size(); i++) {
                int sz = val[i] - val[i - 1];
                C[0][i] = 1;
                for (int j = 1; j <= n; j++) {
                        C[j][i] = C[j - 1][i] * (sz + j - 1) % mod * pw(j, mod - 2) % mod;
                }
                dp[0][i] = 1;
        }

        dp[0][0] = 1;

        for (int i = 1; i <= n; i++) {
                dp[i][0] = 1;
                for (int j = 1; j < (int)val.size(); j++) {
                        dp[i][j] = dp[i][j - 1];
                        int cnt = 0;
                        for (int k = i; k >= 1; k--) {
                                if (l[k] < val[j] && val[j] <= r[k]) {
                                        cnt++;
                                        dp[i][j] += dp[k - 1][j - 1] * C[cnt][j] % mod;
                                        dp[i][j] %= mod;
                                }
                        }
                }
        }

        cout << dp[n][(int)val.size() - 1] - 1;
}

int32_t main() {
        std::ios_base::sync_with_stdio(0);
        std::cin.tie(0); std::cout.tie(0);

        #define TASK ""
        if (fopen(TASK".INP", "r")) {
                freopen(TASK".INP", "r", stdin);
                freopen(TASK".OUT", "w", stdout);
        }

        if (fopen("TASK.INP", "r")) {
                freopen("TASK.INP", "r", stdin);
                freopen("TASK.OUT", "w", stdout);
        }

        /* int TEST = 1; cin >> TEST; while (TEST--) */ Solve();

        cerr << "\nTime elapsed: " << 1.0 * clock() / CLOCKS_PER_SEC << "s\n";
        return 0;
}

Compilation message (stderr)

boat.cpp: In function 'int32_t main()':
boat.cpp:77:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   77 |                 freopen(TASK".INP", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
boat.cpp:78:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   78 |                 freopen(TASK".OUT", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
boat.cpp:82:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   82 |                 freopen("TASK.INP", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
boat.cpp:83:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   83 |                 freopen("TASK.OUT", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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