Submission #645054

#	Time	Username	Problem	Language	Result	Execution time	Memory
645054		ghostwriter	Boat (APIO16_boat)	C++14	100 / 100	1545 ms	10196 KiB

boat

#include <bits/stdc++.h>
using namespace std;
#ifdef LOCAL
#include <debug.h>
#endif
#define ft front
#define bk back
#define st first
#define nd second
#define ins insert
#define ers erase
#define pb push_back
#define pf push_front
#define _pb pop_back
#define _pf pop_front
#define lb lower_bound
#define ub upper_bound
#define mtp make_tuple
#define bg begin
#define ed end
#define all(x) (x).bg(), (x).ed()
#define sz(x) (int)(x).size()
typedef long long ll; typedef unsigned long long ull;
typedef double db; typedef long double ldb;
typedef pair<int, int> pi; typedef pair<ll, ll> pll;
typedef vector<int> vi; typedef vector<ll> vll; typedef vector<pi> vpi; typedef vector<pll> vpll;
typedef string str;
template<typename T> T gcd(T a, T b) { return (b == 0? a : gcd(b, a % b)); }
template<typename T> T lcm(T a, T b) { return a / gcd(a, b) * b; }
#define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
#define FOS(i, r, l) for (int (i) = (r); (i) >= (l); --(i))
#define FRN(i, n) for (int (i) = 0; (i) < (n); ++(i))
#define FSN(i, n) for (int (i) = (n) - 1; (i) >= 0; --(i))
#define EACH(i, x) for (auto &(i) : (x))
#define WHILE while
#define file "TEST"
mt19937 rd(chrono::steady_clock::now().time_since_epoch().count());
ll rand(ll l, ll r) { return uniform_int_distribution<ll>(l, r)(rd); }
/*
----------------------------------------------------------------
    END OF TEMPLATE
----------------------------------------------------------------
    Tran The Bao - ghostwriter
    Training for VOI23 gold medal
----------------------------------------------------------------
    DIT ME CHUYEN BAO LOC
----------------------------------------------------------------
*/
const int M = 1e9 + 7;
const int N = 502;
const int Nx2 = 1002;
int n, m, inv[N], d[Nx2][N][2], d1[Nx2][N][2], d2[Nx2][N];
pi a[N], a1[N];
vpi seg;
int fpow(int a, int b, int M) {
    if (b == 0) return 1;
    int tmp = fpow(a, b >> 1, M);
    if (b & 1) return 1LL * tmp * tmp % M * a % M;
    return 1LL * tmp * tmp % M;
}
signed main() {
    ios_base::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    // freopen(file".inp", "r", stdin);
    // freopen(file".out", "w", stdout);
    cin >> n;
    FOR(i, 1, n) {
        cin >> a[i].st >> a[i].nd;
        a1[i] = a[i];
    }
    sort(a1 + 1, a1 + 1 + n);
    FOR(i, 1, n) {
        if (i == 1) {
            seg.pb(a1[i]);
            continue;
        }
        if (a1[i].st > seg.bk().nd) {
            seg.pb(a1[i]);
            continue;
        }
        vpi seg1;
        EACH(j, seg) {
            int l = j.st, r = j.nd;
            if (l <= a1[i].st && a1[i].nd <= r) {
                if (l < a1[i].st) seg1.pb({l, a1[i].st - 1});
                seg1.pb(a1[i]);
                if (r > a1[i].nd) seg1.pb({a1[i].nd + 1, r});
            }
            else if (l < a1[i].st && r >= a1[i].st) {
                seg1.pb({l, a1[i].st - 1});
                seg1.pb({a1[i].st, r});
            }
            else if (l <= a1[i].nd && r > a1[i].nd) {
                seg1.pb({l, a1[i].nd});
                seg1.pb({a1[i].nd + 1, r});
            }
            else seg1.pb({l, r});
        }
        if (a1[i].nd > seg1.bk().nd) seg1.pb({seg1.bk().nd + 1, a1[i].nd});
        swap(seg, seg1);
    }
    reverse(all(seg));
    seg.pb({-1, -1});
    reverse(all(seg));
    m = sz(seg) - 1;
    FOR(i, 1, n) inv[i] = fpow(i, M - 2, M);
    FOR(i, 1, m) {
        d2[i][0] = 1;
        int cnt = min(n, seg[i].nd - seg[i].st + 1);
        FOR(j, 1, cnt) d2[i][j] = 1LL * d2[i][j - 1] * (seg[i].nd - seg[i].st + 2 - j) % M * inv[j] % M;
    }
    FOR(i, 1, m)
    FOR(j, 0, n)
    FOR(z, 0, 1)
        d1[i][j][z] = d2[i][j];
    FOR(i, 1, n) {
        FOR(j, 1, m)
        FOR(z, 0, n - i)
        FOR(stat, 0, 1) {
            int &rs = d[j][z][stat];
            rs = 0;
            if (stat) rs = (rs + d1[j][z][1]) % M;
            if (a[i].st <= seg[j].st && seg[j].nd <= a[i].nd) rs = (rs + d1[j][z + 1][1]) % M;
            if (j > 1) rs = (rs + 1LL * d2[j][z] * d[j - 1][0][0] % M) % M;
        }
        FOR(j, 1, m)
        FOR(z, 0, n - i)
        FOR(stat, 0, 1)
            d1[j][z][stat] = d[j][z][stat];
    }
    cout << (d[m][0][1] - 1 + M) % M;
    return 0;
}
/*
2
1 5
3 3
----------------------------------------------------------------
From Benq:
    stuff you should look for
        * int overflow, array bounds
        * special cases (n=1?)
        * do smth instead of nothing and stay organized
        * WRITE STUFF DOWN
        * DON'T GET STUCK ON ONE APPROACH
----------------------------------------------------------------
*/

Compilation message (stderr)

boat.cpp: In function 'int main()':
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:66:5: note: in expansion of macro 'FOR'
   66 |     FOR(i, 1, n) {
      |     ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:71:5: note: in expansion of macro 'FOR'
   71 |     FOR(i, 1, n) {
      |     ^~~
boat.cpp:34:31: warning: unnecessary parentheses in declaration of 'j' [-Wparentheses]
   34 | #define EACH(i, x) for (auto &(i) : (x))
      |                               ^
boat.cpp:81:9: note: in expansion of macro 'EACH'
   81 |         EACH(j, seg) {
      |         ^~~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:105:5: note: in expansion of macro 'FOR'
  105 |     FOR(i, 1, n) inv[i] = fpow(i, M - 2, M);
      |     ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:106:5: note: in expansion of macro 'FOR'
  106 |     FOR(i, 1, m) {
      |     ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'j' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:109:9: note: in expansion of macro 'FOR'
  109 |         FOR(j, 1, cnt) d2[i][j] = 1LL * d2[i][j - 1] * (seg[i].nd - seg[i].st + 2 - j) % M * inv[j] % M;
      |         ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:111:5: note: in expansion of macro 'FOR'
  111 |     FOR(i, 1, m)
      |     ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'j' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:112:5: note: in expansion of macro 'FOR'
  112 |     FOR(j, 0, n)
      |     ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'z' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:113:5: note: in expansion of macro 'FOR'
  113 |     FOR(z, 0, 1)
      |     ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'i' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:115:5: note: in expansion of macro 'FOR'
  115 |     FOR(i, 1, n) {
      |     ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'j' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:116:9: note: in expansion of macro 'FOR'
  116 |         FOR(j, 1, m)
      |         ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'z' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:117:9: note: in expansion of macro 'FOR'
  117 |         FOR(z, 0, n - i)
      |         ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'stat' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:118:9: note: in expansion of macro 'FOR'
  118 |         FOR(stat, 0, 1) {
      |         ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'j' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:125:9: note: in expansion of macro 'FOR'
  125 |         FOR(j, 1, m)
      |         ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'z' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:126:9: note: in expansion of macro 'FOR'
  126 |         FOR(z, 0, n - i)
      |         ^~~
boat.cpp:30:31: warning: unnecessary parentheses in declaration of 'stat' [-Wparentheses]
   30 | #define FOR(i, l, r) for (int (i) = (l); (i) <= (r); ++(i))
      |                               ^
boat.cpp:127:9: note: in expansion of macro 'FOR'
  127 |         FOR(stat, 0, 1)
      |         ^~~

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