Submission #943804

#	Time	Username	Problem	Language	Result	Execution time	Memory
943804		Boycl07	Boat (APIO16_boat)	C++17	9 / 100	1403 ms	7064 KiB

boat

#include <bits/stdc++.h>

using namespace std;

typedef long long ll;

#define rep(i, n) for(int i = 1; i <= n; ++i)
#define forn(i, l, r) for(int i = l; i <= r; ++i)
#define ford(i, r, l) for(int i = r; i >= l; --i)
#define FOR(i, n) for(int i = 0; i < n; ++i)
#define FORD(i, n) for(int i = n - 1; i >= 0; --i)
#define fi first
#define se second
#define pii pair<int, int>
#define pll pair<ll, ll>
#define pb push_back
#define endl "\n"
#define task "boat"
#define sz(a) int(a.size())
#define C(x, y) make_pair(x, y)
#define all(a) (a).begin(), (a).end()
#define bit(i, mask) (mask >> i & 1)

template<typename T> bool maximize(T &res, const T &val) { if (res < val){ res = val; return true; }; return false; }
template<typename T> bool minimize(T &res, const T &val) { if (res > val){ res = val; return true; }; return false; }

inline int readInt()       {char c;while(c=getchar(),c!='-'&&(c<'0'||c>'9'));bool sign=(c=='-');if(sign)c=getchar();int n=c-'0';while(c=getchar(),c>='0'&&c<='9')n=10*n+c-'0';return(!sign)?n:-n;}
inline ll readLong()       {char c;while(c=getchar(),c!='-'&&(c<'0'||c>'9'));bool sign=(c=='-');if(sign)c=getchar();ll  n=c-'0';while(c=getchar(),c>='0'&&c<='9')n=10*n+c-'0';return(!sign)?n:-n;}
inline string readString() {char c;while(c=getchar(),c==' '||c=='\n'||c=='\t');string s({c});while(c=getchar(),c!=EOF&&c!=' '&&c!='\n'&&c!='\t')s+=c;return s;}


const int N =  1e3 + 10;
const int M = 1e3 + 3;
const int N1 = 2e3 + 10;
const int K = 1e2 + 1;
const int MOD = 1e9 + 7;
const int INF = 0x3f3f3f3f;
const ll LINF = 1e17 + 2;
const int block_size = 500;
const int LOG = 40;
const int offset = N;
const int LIM = 11 ;
const int AL = 26;

int add(int x, int y)
{
    x += y;
    if(x >= MOD) x -= MOD;
    if(x < 0) x += MOD;
    return x;
}

int mul(int x, int y)
{
    return 1ll * x * y % MOD;
}

int n;

int a[N], b[N];

int C[N][N];

int comb[N], inv[N];

int dp[N][N];

vector<int> zip;

void solve()
{
    cin >> n;
    rep(i, n)
    {
        cin >> a[i] >> b[i];
        zip.pb(a[i]);
        zip.pb(b[i] + 1);
    }
    sort(all(zip));
    zip.resize(unique(all(zip)) - zip.begin());
    rep(i, n) rep(j, n) C[i][j] = add(C[i - 1][j], C[i][j - 1]);

//    rep(i, n) a[i] = upper_bound(all(zip), a[i]) - zip.begin();
//    rep(i, n) b[i] = upper_bound(all(zip), b[i]) - zip.begin();

    int m = sz(zip);
    dp[0][0] = 1;
    inv[0] = inv[1] = 1;
    forn(i, 2, 2 * n) inv[i] = add(MOD, -mul(inv[MOD % i], MOD / i));
    forn(i, 0, m - 1)
    {
        int l, r;
        l = zip[i], r = i == m - 1 ? zip[i] + 1 : zip[i + 1];
        forn(j, 0, n)
        {
            dp[i + 1][j] = add(dp[i + 1][j], dp[i][j]);
            int cnt = 0, cur = 1;
            comb[0] = 0;
            forn(k, 1, n)
            {
                cur = mul(cur, mul(inv[k - 1], r - l - k + 1));
                comb[k] = add(comb[k - 1], cur);
            }
            forn(k, j + 1, n)
            {
                if(a[k] <= l && b[k] >= r - 1)
                {
                    dp[i + 1][k] = add(dp[i + 1][k], mul(dp[i][j], comb[++cnt]));
                }
            }
        }
    }
//    rep(i, m)
//    {
//        rep(j, n) cout << i << " " << j << endl << dp[i][j] << endl << endl;
//    }
    int res = 0;
    forn(i, 1, n) res = add(res, dp[m][i]);
    cout << res << endl;
}

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

    int TC = 1;

    if(fopen(task".inp", "r"))
    {
        freopen(task".inp", "r", stdin);
        freopen(task".out", "w", stdout);
    }


    while(TC--)
    {
        solve();
        cout << endl;
    }

    return 0;
}

Compilation message (stderr)

boat.cpp: In function 'int main()':
boat.cpp:131:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  131 |         freopen(task".inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
boat.cpp:132:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  132 |         freopen(task".out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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