Submission #946337

#	Time	Username	Problem	Language	Result	Execution time	Memory
946337		simona1230	Boat (APIO16_boat)	C++17	0 / 100	3 ms	4696 KiB

boat

#include <bits/stdc++.h>

using namespace std;
long long n;
pair<long long,long long> p[200001],a[200001];

void read()
{
    cin>>n;
    for(long long i=1;i<=n;i++)
    {
        cin>>p[i].first>>p[i].second;
    }
    sort(p+1,p+n+1);

    long long last=0;
    for(long long i=1;i<=n;i++)
    {
        long long len=p[i].second-p[i].first;
        a[i].first=a[i-1].second+1;

        if(p[i-1].second>=p[i].first)
        {
            long long same=p[i-1].second-p[i].first;
            a[i].first=a[i-1].second-same;
        }

        a[i].second=a[i].first+len;
        //cout<<a[i].first<<" "<<a[i].second<<endl;
    }
}

const long long mod=1e9+7;
long long t[4000001];

long long query(long long i,long long l,long long r,long long ql,long long qr)
{
    if(ql>qr)return 0;
    if(l>=ql&&r<=qr)
    {
        //cout<<i<<" "<<l<<" "<<r<<" "<<t[i]<<" query"<<endl;
        return t[i];
    }
    long long m=(l+r)/2;
    return (query(i*2,l,m,ql,min(qr,m))+query(i*2+1,m+1,r,max(ql,m+1),qr))%mod;
}

void update(long long i,long long l,long long r,long long idx,long long val)
{
    if(l==r)
    {
        t[i]+=val;
        t[i]%=mod;
        return;
    }
    long long m=(l+r)/2;
    if(m>=idx)update(i*2,l,m,idx,val);
    else update(i*2+1,m+1,r,idx,val);
    t[i]=t[i*2]+t[i*2+1];
    t[i]%=mod;
    //cout<<i<<" "<<l<<" "<<r<<" "<<t[i]<<endl;
}
void solve()
{
    update(1,0,a[n].second,0,1);

    for(long long i=1;i<=n;i++)
    {
        for(long long j=a[i].second;j>=a[i].first;j--)
        {
            long long help=query(1,0,a[n].second,0,j-1);
            //cout<<i<<" "<<j<<" "<<dp[i][j]<<endl;
            update(1,0,a[n].second,j,help);
        }
    }
    cout<<query(1,0,a[n].second,1,a[n].second)<<endl;
}
int main()
{
	ios_base::sync_with_stdio(false);
	cin.tie(NULL);
	cout.tie(NULL);
	read();
	solve();
	return 0;
}

Compilation message (stderr)

boat.cpp: In function 'void read()':
boat.cpp:16:15: warning: unused variable 'last' [-Wunused-variable]
   16 |     long long last=0;
      |               ^~~~

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