제출 #306958

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
306958		MarcoMeijer	Boat (APIO16_boat)	C++14	100 / 100	1952 ms	24568 KiB

boat

#include <bits/stdc++.h>
using namespace std;
 
// macros
typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<ll, ll> lll;
typedef tuple<int, int, int> iii;
typedef vector<int> vi;
typedef vector<ii> vii;
typedef vector<iii> viii;
typedef vector<ll> vll;
typedef vector<lll> vlll;
#define REP(a,b,c) for(int a=int(b); a<int(c); a++)
#define RE(a,c) REP(a,0,c)
#define RE1(a,c) REP(a,1,c+1)
#define REI(a,b,c) REP(a,b,c+1)
#define REV(a,b,c) for(int a=int(c-1); a>=int(b); a--)
#define FOR(a,b) for(auto& a : b)
#define all(a) a.begin(), a.end()
#define INF 1e18
#define EPS 1e-9
#define pb push_back
#define popb pop_back
#define fi first
#define se second
#define sz size()
mt19937_64 rng(chrono::steady_clock::now().time_since_epoch().count());
 
// input
template<class T> void IN(T& x) {cin >> x;}
template<class H, class... T> void IN(H& h, T&... t) {IN(h); IN(t...); }
 
// output
template<class T1, class T2> void OUT(const pair<T1,T2>& x);
template<class T> void OUT(const vector<T>& x);
template<class T> void OUT(const T& x) {cout << x;}
template<class H, class... T> void OUT(const H& h, const T&... t) {OUT(h); OUT(t...); }
template<class T1, class T2> void OUT(const pair<T1,T2>& x) {OUT(x.fi,' ',x.se);}
template<class T> void OUT(const vector<T>& x) {RE(i,x.size()) OUT(i==0?"":" ",x[i]);}
template<class... T> void OUTL(const T&... t) {OUT(t..., "\n"); }
template<class H> void OUTLS(const H& h) {OUTL(h); }
template<class H, class... T> void OUTLS(const H& h, const T&... t) {OUT(h,' '); OUTLS(t...); }
 
//===================//
//  Added libraries  //
//===================//

// mod library
ll MOD=1e9+7;

inline ll mod(ll x_) {
    return (x_)%MOD;
}
ll modpow(ll x_, ll N_) {
    if(N_ == 0) return 1;
    ll a = modpow(x_,N_/2);
    a = (a*a)%MOD;
    if(N_%2) a = (a*x_)%MOD;
    return a;
}
ll inv(ll x_) {
    return modpow(x_, MOD-2);
}
class mi {
public:
    mi(ll v=0) {value = v;}
    mi  operator+ (ll rs) {return value+rs;}
    mi  operator- (ll rs) {return mod(value-rs+MOD);}
    mi  operator* (ll rs) {return mod(value*rs);}
    mi  operator/ (ll rs) {return mod(value*inv(rs));}
    mi& operator+=(ll rs) {*this = (*this)+rs; return *this;}
    mi& operator-=(ll rs) {*this = (*this)-rs; return *this;}
    mi& operator*=(ll rs) {*this = (*this)*rs; return *this;}
    mi& operator/=(ll rs) {*this = (*this)/rs; return *this;}
    operator ll&() {return value;}

    ll value;
};
typedef vector<mi> vmi;

//===================//
//end added libraries//
//===================//
 
void program();
int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    program();
}
 
 
//===================//
//   begin program   //
//===================//
 
const int MX = 1010;

int n, m;
int a[MX], b[MX];
mi FACT[MX];
mi RFACT[MX];
mi RFACT2[MX];
mi ways[MX][MX];
mi ways2[MX][MX];
mi dp[MX][MX];
vi cc;
ll len[MX];

mi fact(int i) {
    if(i < 0) return 0;
    return FACT[i];
}
mi rfact(int i) {
    if(i < 0) return 0;
    return RFACT[i];
}
mi rfact2(int i) {
    if(i < 0) return 0;
    return RFACT2[i];
}
mi get(int i, int j) {
    if(i < 0) return 1;
    if(j < 0) return 0;
    return dp[i][j];
}
mi getW(int i, int j) {
    if(ways[i][j] != -1) return ways[i][j];
    mi res = 0;
    mi cFact = 1; ll factNumb = len[i];
    RE1(i,j) {
        cFact *= factNumb; factNumb--;
        res += cFact*rfact2(i)*rfact(j-i);
    }
    res %= MOD;
    return ways[i][j] = res*fact(j);
}
mi getWays(int i, int j) {
    if(ways2[i][j] != -1) return ways2[i][j];
    return ways2[i][j] = getW(i,j)-getW(i,j-1);
}

void program() {
    IN(n);
    RE(i,n) IN(a[i], b[i]);
    RE(i,n) b[i]++;

    FACT[0]=1;
    REP(i,1,MX) FACT[i] = FACT[i-1]*mi(i);
    REP(i,0,MX) RFACT[i] = mi(1)/FACT[i];
    REP(i,0,MX) RFACT2[i] = RFACT[i]*RFACT[i];

    // coördinate compression
    RE(i,n) cc.pb(a[i]), cc.pb(b[i]);
    sort(all(cc));
    cc.erase(unique(all(cc)),cc.end());
    RE(i,n) a[i] = lower_bound(all(cc),a[i])-cc.begin();
    RE(i,n) b[i] = lower_bound(all(cc),b[i])-cc.begin();
    m = cc.size();

    RE(i,m-1) len[i] = cc[i+1]-cc[i];
    RE(i,m-1) RE(j,n+1) ways[i][j] = ways2[i][j] = -1;

    RE(i,n) RE(j,m) {
        dp[i][j] = get(i,j-1);
        if(a[i] <= j && j < b[i]) {
            int inRange = 0;
            REV(k,0,i+1) {
                if(a[k] <= j && j < b[k]) inRange++;
                mi w = getWays(j,inRange);
                dp[i][j] += get(k-1,j-1)*w;
            }
            dp[i][j] %= MOD;
        }
    }

    mi ans = 0;
    RE(i,n) ans += dp[i][m-1];
    ans %= MOD;
    OUTL((ll)ans);
}

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