Submission #578169

#	Time	Username	Problem	Language	Result	Execution time	Memory
578169		lam	Knapsack (NOI18_knapsack)	C++17	0 / 100	8 ms	10068 KiB

knapsack

#include <iostream>
#include <vector>
#include <queue>
#include <algorithm>
#include <cmath>
#define maxn 2010
//#define int long long
#define taskname "spainting"
using namespace std;
int s,n;
int dp[maxn][maxn];
vector <pair<int,int>> a[maxn];
signed main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr); cout.tie(nullptr);
//    freopen(taskname".in","r",stdin);
//    freopen(taskname".out","w",stdout);
    cin>>s>>n;
    for (int i=1; i<=n; i++)
    {
        int v,w,k; cin>>v>>w>>k;
        if (w<=s&&k>0) a[w].push_back({v,k});
    }
    for (int i=0; i<=s; i++) for (int j=0; j<=s; j++) dp[i][j]=-1e18;
    dp[0][0]=0;
    for (int i=1; i<=s; i++)
    {
        sort(a[i].begin(),a[i].end(),greater<pair<int,int>>());
        for (int j=0; j<=s; j++)
        {
            dp[i][j]=dp[i-1][j];
            if (a[i].empty()) continue;
            int cnt=0;
            int used=0;
            int it=0;
            int sum=0;
            while ((cnt+1)*i<=j&&it<a[i].size())
            {
                cnt++;
                sum+=a[i][it].first;
                if (dp[i-1][j-cnt*i]!=1e18)
                    dp[i][j]=max(dp[i][j],dp[i-1][j-cnt*i]+sum);
                used++;
                if (used==a[i][it].second)
                {
                    used=0;
                    it++;
                }
            }
        }
    }
    int ans=-1e18;
    for (int i=0; i<=s; i++) ans=max(ans,dp[n][i]);
    cout<<ans;
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:25:64: warning: overflow in conversion from 'double' to 'int' changes value from '-1.0e+18' to '-2147483648' [-Woverflow]
   25 |     for (int i=0; i<=s; i++) for (int j=0; j<=s; j++) dp[i][j]=-1e18;
      |                                                                ^~~~~
knapsack.cpp:38:36: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |             while ((cnt+1)*i<=j&&it<a[i].size())
      |                                  ~~^~~~~~~~~~~~
knapsack.cpp:53:13: warning: overflow in conversion from 'double' to 'int' changes value from '-1.0e+18' to '-2147483648' [-Woverflow]
   53 |     int ans=-1e18;
      |             ^~~~~

• Subtask 1: 0 / 12
• Subtask 2: 0 / 17
• Subtask 3: 0 / 20
• Subtask 4: 0 / 24
• Subtask 5: 0 / 27