Submission #1187504

#	Time	Username	Problem	Language	Result	Execution time	Memory
1187504		asli_bg	Boat (APIO16_boat)	C++20	0 / 100	5 ms	8264 KiB

boat

#include <bits/stdc++.h>
using namespace std;

#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;

#define int long long

typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<pii> vii;
typedef vector<bool> vb;

typedef tree<pii,null_type,less<pii>,rb_tree_tag,
tree_order_statistics_node_update> oset;

#define fi first
#define se second
#define pb push_back
#define pf push_front

#define mid (l+r)/2
#define all(x) x.begin(),x.end()
#define FOR(i,a) for(int i=0;i<(a);i++)
#define FORE(i,a,b) for(int i=(a);i<(b);i++)

#define cont(x) for(auto el:x) cout<<el<<' ';cout<<endl;
#define contp(x) for(auto el:x) cout<<el.fi<<'-'<<el.se<<' ';cout<<endl;
#define sp <<" "<<

#define DEBUG(x) cout<<(#x) sp x<<endl
#define carp(a,b) (((a%MOD)*(b%MOD))%MOD)
#define topla(a,b) (((a%MOD)+(b%MOD))%MOD)

const int INF=1e18;
const int MAXN=1e3+5;
const int MOD=1e9+7;

int dp[MAXN][MAXN];
/*dp[i][j] --> i.segmente kadar j.ye kadarki okulları kullandım 
               kaç farklı yol var*/

int fac[MAXN], inv[MAXN];

int exp(int x,int us){
    int res=1;
    while(us>0){
        if(us&1) res=carp(res,x);
        x=carp(x,x);
        us/=2;
    }
    return res;
}

void calc(){
    fac[0]=fac[1]=1;
    FORE(i,2,MAXN){
        fac[i]=carp(fac[i-1],i);
        inv[i]=exp(fac[i],MOD-2);
    }
}

int comb(int n,int r){
    if(r>n) return 0;
    return carp(fac[n],carp(inv[n-r],inv[r]));
}

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

    calc();

    int n;
    cin>>n;
    vi a(n+1),b(n+1);

    set<int> s;
    FORE(i,1,n+1){
        cin>>a[i]>>b[i];
        s.insert(a[i]);
        s.insert(b[i]+1);
    }

    vi vec;
    for(auto el:s) vec.pb(el);
    
    vii ara;
    ara.pb({0,0});
    FORE(i,1,vec.size()){
        ara.pb({vec[i-1],vec[i]-1});
    }

    //contp(ara);

    int sz=ara.size();

    int ans=0;
    dp[0][0]=1;
    FORE(i,1,sz){
        int len=ara[i].se-ara[i].fi+1;
        //DEBUG(len);
        dp[i][0]=1;
        FORE(j,1,n+1){ //j.ye kadar okulları kullan
            dp[i][j]=dp[i-1][j];
            int say=1;
            int mult=len;
            if(a[j]<=ara[i].fi and ara[i].se<=b[j]){
                //cout<<"hh" sp i sp j<<endl;
                for(int k=j-1;k>=0;k--){ //k.okuldan j.ye geç
                    //cout<<"here" sp i-1 sp k sp dp[i-1][k]<<endl;
                    dp[i][j]=topla(dp[i][j],carp(dp[i-1][k],mult));

                    if(a[k]<=ara[i].fi and ara[i].se<=b[k]){
                        mult=carp(mult,comb(len+say-1,say));
                        say++;
                    }
                }
            }
        }
    }

    //DEBUG(dp[sz-1][n]);

    FORE(i,1,n+1){
        ans=topla(ans,dp[sz-1][i]);
    }

    cout<<ans<<endl;
}

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