Submission #1113878

#	Time	Username	Problem	Language	Result	Execution time	Memory
1113878		Matkap	Knapsack (NOI18_knapsack)	C++17	49 / 100	1043 ms	504 KiB

knapsack

/*
    Author:Matkap(prefix_sum)
*/
 
#include <bits/stdc++.h>
#include <array>
 
using namespace std;
 
#define int long long
#define endl "\n"
#define ar array
#define all(x) x.begin(),x.end()
 
const int INF = 1e17 , MOD = 1e9 + 7;
 
void setIO(string name = "") 
{
    if (name.size())
    {
        freopen((name + ".in").c_str(), "r", stdin);
        freopen((name + ".out").c_str(), "w", stdout);
    }
}
int mul(int a,int b,int mod = MOD)
{
    a %= mod;
    b %= mod;
    return a * 1LL * b % mod;
}
int sum(int a,int b,int mod = MOD)
{
    a %= mod;
    b %= mod;
    return (a + b + mod) % mod;
}
int binpow(int base,int power,int mod = MOD)
{
    if(power == 1) return base;
    if(power == 0) return 1;
    
    if(power%2==1)
    {
         int a;    
         a = binpow(base,(power - 1)/2);
        return mul(base, mul(a, a, mod), mod);
    } 
    else
     {
        int a;
        a = binpow(base,power/2);
        return mul(a, a, mod);
    } 
 
}
int inv(int a,int mod = MOD)
{
    a %= mod;
    return binpow(a, mod - 2) % mod;
}
void solve()
{
    int n,s;
    cin >> s >> n;
    vector<int> dp(s + 1, -INF), ndp(s + 1);
    vector<ar<int,2>> weights[s + 1];
    dp[0] = 0;
    for(int i = 0;n > i;i++)
    {
        ndp = dp;
        int value, weight, count;
        cin >> value >> weight >> count;
        weights[weight].push_back({value,count});
    } 
    for(auto& it : weights) sort(all(it));
    for(int i = 1;s >= i;i++)
    {
        ndp = dp;
        int used_weight = 0, total_value = 0;
        while(weights[i].size())
        {
            auto& [value, count] = weights[i].back();
            used_weight += i;
            total_value += value;
            for(int j = used_weight;s >= j;j++)
            {
                ndp[j] = max(ndp[j], dp[j - used_weight] + total_value);
            }
            count--;
            if(count == 0) weights[i].pop_back();
        }
        dp = ndp;
    }
    cout << *max_element(all(dp)) << endl;
}
int32_t main()
{
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
 
    int tt;
    tt=1; 
    //cin >> tt;
    while(tt--) solve();
 
}

Compilation message (stderr)

knapsack.cpp: In function 'void setIO(std::string)':
knapsack.cpp:21:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |         freopen((name + ".in").c_str(), "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:22:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |         freopen((name + ".out").c_str(), "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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