oj.uz

Submission #80749

# Submission time Handle Problem Language Result Execution time Memory
80749 2018-10-22T08:07:04 Z polyfish Boat (APIO16_boat) C++14
9 / 100
 101 ms 11636 KB 
#include <bits/stdc++.h>
using namespace std;

const int MAX_N = 502;
const int MOD = 1000000007;

int n;
int64_t f[MAX_N][MAX_N*2], ps[MAX_N][MAX_N*2], C[2*MAX_N][MAX_N], fact[MAX_N];
pair<int, int> s[MAX_N];
vector<pair<int, int> > t;

void enter() {
    cin >> n;
    for (int i=1; i<=n; ++i) {
        cin >> s[i].first >> s[i].second;
    }
}

int64_t pw(int64_t n, int k) {
    if (k==0)
        return 1;
    int64_t tmp = pw(n, k/2);
    if (k%2)
        return tmp * tmp % MOD * n % MOD;
    return tmp * tmp % MOD;
}

void init() {
    vector<int> b;
    for (int i=1; i<=n; ++i) {
        b.push_back(s[i].first);
        b.push_back(s[i].second+1);
    }
    sort(b.begin(), b.end());
    t.push_back(make_pair(0, 0));
    t.push_back(make_pair(0, 0));
    for (int i=0; i+1<b.size(); ++i) {
        if (b[i+1]-1>=b[i])
            t.push_back(make_pair(b[i], b[i+1]-1));
    }
    sort(t.begin(), t.end());
    fact[0] = 1;
    for (int i=1; i<=n; ++i)
        fact[i] = fact[i-1] * i % MOD;
    for (int i=1; i<t.size(); ++i) {
        int len = t[i].second - t[i].first + 1;
        int64_t tmp = 1;
        for (int k=1; k<=min(len, n); ++k) {
            tmp = tmp * (len-k+1) % MOD;
            C[i][k] = tmp * pw(fact[k], MOD-2) % MOD;
        }
    }
}

bool intersect(pair<int, int> p, pair<int, int> q) {
    return !(p.second < q.first || p.first>q.second);
}

void solve() {
    int64_t res = 0;
    f[0][1] = 1;
    for (int j=1; j<t.size(); ++j)
        ps[0][j] = 1;
    for (int i=1; i<=n; ++i) {
        for (int j=1; j<t.size(); ++j) {
            if (intersect(s[i], t[j])) {
                for (int k=i; k>=1; --k) {
                    if (!intersect(t[j], s[k]))
                        break;
                    f[i][j] = (f[i][j] + ps[k-1][j-1] * C[j][i-k+1]) % MOD;
                    //cerr << ps[k-1][j-1] << ' ' << C[t[j].first-t[j].second+1][i-k+1] << '\n';
                }
            }
            res = (res + f[i][j]) % MOD;
        }
        for (int j=1; j<t.size(); ++j)
            ps[i][j] = (ps[i][j-1] + ps[i-1][j] - ps[i-1][j-1] + MOD + f[i][j]) % MOD;
    }
    cout << res;
}

int main() {
    //freopen("boat.inp", "r", stdin);
    //freopen("boat.out", "w", stdout);
    ios::sync_with_stdio(0); cin.tie(0);
    enter();
    init();
    solve();
}

Compilation message

boat.cpp: In function 'void init()':
boat.cpp:37:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=0; i+1<b.size(); ++i) {
                   ~~~^~~~~~~~~
boat.cpp:45:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i=1; i<t.size(); ++i) {
                   ~^~~~~~~~~
boat.cpp: In function 'void solve()':
boat.cpp:62:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int j=1; j<t.size(); ++j)
                   ~^~~~~~~~~
boat.cpp:65:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j=1; j<t.size(); ++j) {
                       ~^~~~~~~~~
boat.cpp:76:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j=1; j<t.size(); ++j)
                       ~^~~~~~~~~

Subtask #1
9.0 / 9.0

# Verdict Execution time Memory Grader output
1 Correct 95 ms 10232 KB Output is correct
2 Correct 93 ms 10420 KB Output is correct
3 Correct 100 ms 10420 KB Output is correct
4 Correct 96 ms 10432 KB Output is correct
5 Correct 95 ms 10480 KB Output is correct
6 Correct 94 ms 10824 KB Output is correct
7 Correct 93 ms 10824 KB Output is correct
8 Correct 93 ms 10824 KB Output is correct
9 Correct 94 ms 10824 KB Output is correct
10 Correct 95 ms 10852 KB Output is correct
11 Correct 94 ms 10852 KB Output is correct
12 Correct 96 ms 10852 KB Output is correct
13 Correct 93 ms 10852 KB Output is correct
14 Correct 101 ms 10912 KB Output is correct
15 Correct 93 ms 10912 KB Output is correct
16 Correct 22 ms 10912 KB Output is correct
17 Correct 24 ms 10912 KB Output is correct
18 Correct 26 ms 10912 KB Output is correct
19 Correct 24 ms 10912 KB Output is correct
20 Correct 23 ms 10912 KB Output is correct

Subtask #2
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 95 ms 10232 KB Output is correct
2 Correct 93 ms 10420 KB Output is correct
3 Correct 100 ms 10420 KB Output is correct
4 Correct 96 ms 10432 KB Output is correct
5 Correct 95 ms 10480 KB Output is correct
6 Correct 94 ms 10824 KB Output is correct
7 Correct 93 ms 10824 KB Output is correct
8 Correct 93 ms 10824 KB Output is correct
9 Correct 94 ms 10824 KB Output is correct
10 Correct 95 ms 10852 KB Output is correct
11 Correct 94 ms 10852 KB Output is correct
12 Correct 96 ms 10852 KB Output is correct
13 Correct 93 ms 10852 KB Output is correct
14 Correct 101 ms 10912 KB Output is correct
15 Correct 93 ms 10912 KB Output is correct
16 Correct 22 ms 10912 KB Output is correct
17 Correct 24 ms 10912 KB Output is correct
18 Correct 26 ms 10912 KB Output is correct
19 Correct 24 ms 10912 KB Output is correct
20 Correct 23 ms 10912 KB Output is correct
21 Incorrect 21 ms 11636 KB Output isn't correct
22 Halted 0 ms 0 KB -

Subtask #3
0 / 27.0

# Verdict Execution time Memory Grader output
1 Incorrect 10 ms 11636 KB Output isn't correct
2 Halted 0 ms 0 KB -

Subtask #4
0 / 42.0

# Verdict Execution time Memory Grader output
1 Correct 95 ms 10232 KB Output is correct
2 Correct 93 ms 10420 KB Output is correct
3 Correct 100 ms 10420 KB Output is correct
4 Correct 96 ms 10432 KB Output is correct
5 Correct 95 ms 10480 KB Output is correct
6 Correct 94 ms 10824 KB Output is correct
7 Correct 93 ms 10824 KB Output is correct
8 Correct 93 ms 10824 KB Output is correct
9 Correct 94 ms 10824 KB Output is correct
10 Correct 95 ms 10852 KB Output is correct
11 Correct 94 ms 10852 KB Output is correct
12 Correct 96 ms 10852 KB Output is correct
13 Correct 93 ms 10852 KB Output is correct
14 Correct 101 ms 10912 KB Output is correct
15 Correct 93 ms 10912 KB Output is correct
16 Correct 22 ms 10912 KB Output is correct
17 Correct 24 ms 10912 KB Output is correct
18 Correct 26 ms 10912 KB Output is correct
19 Correct 24 ms 10912 KB Output is correct
20 Correct 23 ms 10912 KB Output is correct
21 Incorrect 21 ms 11636 KB Output isn't correct
22 Halted 0 ms 0 KB -