Submission #403931

#	Time	Username	Problem	Language	Result	Execution time	Memory
403931		sad	Boat (APIO16_boat)	C++14	9 / 100	2095 ms	301932 KiB

boat

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define pb push_back
using namespace std;
int dp[502][10009],a[500],b[500];
int n;
const int mod=1e9+7;
vector<int>v;
int d(int x,int y)
{
    if(x==n)
        return 1;
    if(y==v.size())
        return 1;
    int &u=dp[x][y];
    if(u!=-1)
        return u;
    u=0;
    u=d(x+1,y);
    if(a[x]<=v[y]&&b[x]>=v[y])
    {
        u+=d(x+1,y+1);
        u%=mod;
        u+=d(x,y+1);
        u%=mod;
        u-=d(x+1,y+1);
        u+=mod;
        u%=mod;
    }
    else
    {
        u+=d(x,y+1);
        u%=mod;
        u-=d(x+1,y+1);
        u+=mod;
        u%=mod;
    }
    return u;
}
set<int>s;
int main()
{
    cin>>n;v.pb(0);
    for(int i=1; i<=n; i++)
    {
        cin>>a[i]>>b[i];
        for(int j=a[i]; j<=b[i]; j++)
        {
            s.insert(j);
        }
    }
    while(s.size()>0)
    {
        v.pb(*s.begin());
        s.erase(s.begin());
    }
    for(int i=0;i<v.size();i++)dp[0][i]=1;
    for(int i=0;i<n+1;i++)dp[i][0]=1;
    for(int i=1; i<n+1; i++)
    {
        for(int j=1; j<v.size(); j++)
        {int u=0;
            u+=dp[i-1][j];
            u%=mod;int x=i,y=j;
            if(a[i]<=v[j]&&b[i]>=v[j])
            {
                u+=dp[x-1][y-1];//cout<<u<<endl;
                u%=mod;
                u+=dp[x][y-1];//cout<<dp[x][y-1]<<endl;
                u%=mod;
                u-=dp[x-1][y-1];
                u+=mod;
                u%=mod;
            }
            else
            {
                u+=dp[x][y-1];
                u%=mod;
                u-=dp[x-1][y-1];
                u+=mod;
                u%=mod;
            }
        dp[i][j]=u;u=0;
        }
    }
    cout<<dp[n][v.size()-1]-1;
}

Compilation message (stderr)

boat.cpp: In function 'int d(int, int)':
boat.cpp:15:9: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   15 |     if(y==v.size())
      |        ~^~~~~~~~~~
boat.cpp: In function 'int main()':
boat.cpp:59:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   59 |     for(int i=0;i<v.size();i++)dp[0][i]=1;
      |                 ~^~~~~~~~~
boat.cpp:63:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   63 |         for(int j=1; j<v.size(); j++)
      |                      ~^~~~~~~~~

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