Submission #500096

#	Time	Username	Problem	Language	Result	Execution time	Memory
500096		SmolBrain	Knapsack (NOI18_knapsack)	C++17	100 / 100	167 ms	247488 KiB

knapsack

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
using namespace std;
using namespace __gnu_pbds;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;

typedef long long int ll;
typedef long double ld;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define endl '\n'
#define pb push_back
#define conts continue
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "YES" << endl
#define no cout << "NO" << endl
#define ff first
#define ss second
#define ceil2(x,y) ((x+y-1) / y)
#define sz(a) a.size()
#define setbits(x) __builtin_popcountll(x)
#ifndef ONLINE_JUDGE
#define debug(x) cout << #x <<" = "; print(x); cout << endl;
#else
#define debug(x)
#endif

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)

bool iseven(ll n) {if ((n & 1) == 0) return true; return false;}

void print(ll t) {cout << t;}
void print(int t) {cout << t;}
void print(string t) {cout << t;}
void print(char t) {cout << t;}
void print(double t) {cout << t;}
void print(ld t) {cout << t;}

template <class T, class V> void print(pair <T, V> p);
template <class T> void print(vector <T> v);
template <class T> void print(set <T> v);
template <class T, class V> void print(map <T, V> v);
template <class T> void print(multiset <T> v);
template <class T, class V> void print(pair <T, V> p) {cout << "{"; print(p.ff); cout << ","; print(p.ss); cout << "}";}
template <class T> void print(vector <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(set <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T> void print(multiset <T> v) {cout << "[ "; for (T i : v) {print(i); cout << " ";} cout << "]";}
template <class T, class V> void print(map <T, V> v) {cout << "[ "; for (auto i : v) {print(i); cout << " ";} cout << "]";}

void usaco(string filename) {
    freopen((filename + ".in").c_str(), "r", stdin);
    freopen((filename + ".out").c_str(), "w", stdout);
}

// #pragma GCC optimize("Ofast")
// #pragma GCC optimize("unroll-loops")
// #pragma GCC target("avx,avx2,sse,sse2,sse3,sse4,popcnt,fma")

const int MOD = 1e9 + 7;
const int maxn = 1e5 + 5;
const int inf1 = 1e9 + 5;
const ll inf2 = 1e18 + 5;

void solve()
{
    // https://usaco.guide/problems/noi-knapsack/solution/#explanation
    int s, n; cin >> s >> n;
    vector< vector<pair<int, int>> > a(s + 5);

    rep1(i, n) {
        int v, w, k; cin >> v >> w >> k;
        a[w].pb({v, k});
    }

    rep1(i, s) sort(rall(a[i]));
    vector<int> val = {0}, weight = {0};

    rep1(i, s) {
        int cnt = s / i;
        vector<pair<int, int>> &v = a[i];

        for (auto &p : v) {
            while (p.ss--) {
                if (cnt <= 0) break;

                val.pb(p.ff);
                weight.pb(i);

                cnt--;
            }
        }
    }

    int m = sz(val) - 1;
    vector<vector<ll>> dp(m + 5, vector<ll>(s + 5));

    rep1(i, m) {
        int v = val[i], w = weight[i];
        rep(j, s + 1) {
            dp[i][j] = dp[i-1][j];
            if(j >= w){
                dp[i][j] = max(dp[i][j], dp[i-1][j-w] + v);
            }
        }
    }

    ll ans = dp[m][s];
    cout << ans << endl;
}

int main()
{
    fastio;

    int t = 1;
    // cin >> t;
    while (t--) {
        solve();
    }

    return 0;
}

Compilation message (stderr)

knapsack.cpp: In function 'void usaco(std::string)':
knapsack.cpp:55:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   55 |     freopen((filename + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:56:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   56 |     freopen((filename + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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