Submission #1075577

#	Time	Username	Problem	Language	Result	Execution time	Memory
1075577		Faisal_Saqib	Catfish Farm (IOI22_fish)	C++17	15 / 100	1042 ms	199976 KiB

fish

#include <bits/stdc++.h>
using namespace std;
#define ll long long
#define vll vector<ll>
#define all(x) begin(x),end(x)
const int N=1e5+10;
map<ll,ll> pre[N];
map<ll,ll> dp[N][3];
vll possible[N];
vector<pair<ll,ll>> values[N];
ll solve(ll&n,ll&m,vll&x,vll&y,vll&w)
{
    ll ans=0;
    for(int j=0;j<m;j++)
    {
        values[x[j]].push_back({y[j]+1,w[j]});
        possible[x[j]].push_back(y[j]+1),possible[x[j]+1].push_back(y[j]+1);
        if(x[j]>0)
            possible[x[j]-1].push_back(y[j]+1);
    }
    for(int i=0;i<=n;i++)
    {
        possible[i].push_back(0);
        sort(begin(possible[i]),end(possible[i]));
        sort(begin(values[i]),end(values[i]));
        ll sm=0;
        int pp=0;
        for(auto&j:possible[i])
        {
            while(pp<values[i].size() and values[i][pp].first<=j)
            {
                sm+=values[i][pp].second;
                pp++;
            }
            pre[i][j]=sm;
        }
    }
    // for(int i=0;i<n;i++)
    //     for(int j=0;j<=n;j++)
    //         for(int k=0;k<2;k++)
    //             dp[i][j][k]=0;
    for(auto&h:possible[0])
    {
        dp[0][0][h]=0;
        dp[0][1][h]=0;
    }
    for(int i=1;i<n;i++)
    {
        // ll sum=0;
        ll mx1=-2e18;
        ll mx2=-2e18;
        ll mx11=0,mx22=0;
        for(auto&ip:dp[i-1][0])
        {
            int hp=ip.first;
            mx11=max(mx11,ip.second);

            mx1=max(mx1,ip.second-pre[i-1][hp]);
        }
        for(auto&ip:dp[i-1][1])
        {
            int hp=ip.first;
            mx22=max(mx22,ip.second);
            mx2=max(mx2,ip.second+pre[i][hp]);
        }
        for(auto&h:possible[i])
        {
            dp[i][0][h]=max(dp[i][0][h],mx1+pre[i-1][h]);
            dp[i][1][h]=max(dp[i][1][h],mx1+pre[i-1][h]);
            dp[i][1][h]=max(dp[i][1][h],mx2-pre[i][h]);

            dp[i][0][h]=max(dp[i][0][h],mx11);
            dp[i][0][h]=max(dp[i][0][h],mx22);

            dp[i][1][h]=max(dp[i][1][h],mx11);
            dp[i][1][h]=max(dp[i][1][h],mx22);
            // sum+=val[i-1][h];
            // ll aux=0;
            // for(int nh=h+1;nh<=n;nh++)
            // {
            //     // aux+=val[i][nh];
            //     dp[i][h][0]=max(dp[i][h][0],dp[i-1][nh][0]);
            //     dp[i][h][0]=max(dp[i][h][0],dp[i-1][nh][1]);
                
            //     dp[i][h][1]=max(dp[i][h][1],dp[i-1][nh][0]);
            //     dp[i][h][1]=max(dp[i][h][1],dp[i-1][nh][1]+pre[i][nh]-pre[i][h]);

            // }
            // // ll og=sum;
            // for(int nh=0;nh<=h;nh++)
            // {
            //     // sum-=val[i-1][nh];
            //     dp[i][h][0]=max(dp[i][h][0],dp[i-1][nh][0]+pre[i-1][h]-pre[i-1][nh]);
            //     dp[i][h][0]=max(dp[i][h][0],dp[i-1][nh][1]);
                
            //     dp[i][h][1]=max(dp[i][h][1],dp[i-1][nh][0]+pre[i-1][j]-pre[i-1][nh]);
            //     dp[i][h][1]=max(dp[i][h][1],dp[i-1][nh][1]);
            // }
            // sum=og;
        }
    }
    for(int i=0;i<n;i++)
    {
        for(auto&ip:dp[i][0])
        {
            // cout<<"AT "<<ip.first<<' '<<i<<' '<<ip.second<<endl;
            ans=max(ans,ip.second);
        }
        for(auto&ip:dp[i][1])
        {
            // cout<<"AT1 "<<ip.first<<' '<<i<<' '<<ip.second<<endl;
            ans=max(ans,ip.second);
        }
    }
    return ans;
}
ll subtask2(ll&n,ll&m,vll&x,vll&y,vll&w)
{
    ll ans=0;
    ll val[2][n]={0};
    for(int i=0;i<2;i++)
    {
        for(int j=0;j<n;j++)
        {
            val[i][j]=0;
        }
    }
    ll sum1=0,sum0=0;
    for(int j=0;j<m;j++)
    {
        val[x[j]][y[j]]+=w[j];
        if(x[j]==1)
        {
            sum1+=w[j];
        }
        else
        {
            sum0+=w[j];
        }
    }
    ans=max(sum0,sum1);
    ll taken=0;
    ll cur=0;
    for(int j=0;j<n;j++)
    {
        cur+=val[0][j];
        taken+=val[1][j];
        ans=max(ans,cur);
        if(n>2)
            ans=max(ans,cur+sum1-taken);
    }
    return ans;
}
ll subtask3(ll&n,ll&m,vll&x,vll&y,vll&w)
{
    ll ans=0;
    ll val[n+1];
    for(int i=0;i<n;i++)val[i]=0;
    for(int j=0;j<m;j++)val[x[j]]+=w[j];
    ll dp[n+1][3][3];
    for(int i=0;i<n;i++)
        for(int j=0;j<2;j++)
            for(int k=0;k<2;k++)
                dp[i][j][k]=0;
    for(int i=1;i<n;i++)
    {
        // wall not at i
        dp[i][0][0]=max(max(dp[i-1][0][0],dp[i-1][0][1]),dp[i-1][1][0]);
        dp[i][0][1]=max(max(dp[i-1][0][0],dp[i-1][0][1]),dp[i-1][1][0]+val[i]);

        dp[i][1][0]=max(max(dp[i-1][0][1],dp[i-1][0][0]+val[i-1]),dp[i-1][1][0]);
    }
    for(int i=0;i<n;i++)
    {
        ans=max({ans,dp[i][0][0],dp[i][0][1],dp[i][1][0],dp[i][1][1]});
    }
    return ans;
}
long long max_weights(int N, int M, std::vector<int> X, std::vector<int> Y,std::vector<int> W)
{
    ll n=N,m=M,ans=0;
    vector<ll> x(all(X)),y(all(Y)),w(all(W));
    ll mx_x=*max_element(all(x));
    // if(n<=3000)
        return solve(n,m,x,y,w);
    if(mx_x<=1)
        return subtask2(n,m,x,y,w);
    return subtask3(n,m,x,y,w);
}

Compilation message (stderr)

fish.cpp: In function 'long long int solve(long long int&, long long int&, std::vector<long long int>&, std::vector<long long int>&, std::vector<long long int>&)':
fish.cpp:30:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   30 |             while(pp<values[i].size() and values[i][pp].first<=j)
      |                   ~~^~~~~~~~~~~~~~~~~
fish.cpp: In function 'long long int max_weights(int, int, std::vector<int>, std::vector<int>, std::vector<int>)':
fish.cpp:181:16: warning: unused variable 'ans' [-Wunused-variable]
  181 |     ll n=N,m=M,ans=0;
      |                ^~~

• Subtask 1: 0 / 3
• Subtask 2: 6 / 6
• Subtask 3: 9 / 9
• Subtask 4: 0 / 14
• Subtask 5: 0 / 21
• Subtask 6: 0 / 17
• Subtask 7: 0 / 14
• Subtask 8: 0 / 16