Submission #890586

#	Time	Username	Problem	Language	Result	Execution time	Memory
890586		Flan312	Knapsack (NOI18_knapsack)	C++17	100 / 100	35 ms	6100 KiB

knapsack

#include <bits/stdc++.h>
#define ll long long
#define ld long double
#define eb emplace_back
#define task ""
#define fast ios::sync_with_stdio(0),cin.tie(0),cout.tie(0);
#define nx freopen (task".inp","r",stdin), freopen (task".out","w",stdout);
#define fi first
#define se second
#define pii pair <ll, ll>
#define tii tuple <int, int, int>
using namespace std;
const int nmax = 1e5 + 2;
int s, n, v[nmax], w[nmax], k[nmax];
int mxk = 0;
void sub23()
{
    vector<ll> dp(s + 1, 0);
    for (int i = 1; i <= n; ++i)
        for (int j = s; j >= w[i]; --j)
            for (int use = k[i]; use >= 0; --use)
                if (j >= 1ll * w[i] * use)
                    dp[j] = max(dp[j], dp[j - w[i] * use] + 1ll * v[i] * use);
    cout << dp[s];
    exit(0);
}
void sub45()
{
    vector <vector <pii>> lst;
    lst.resize(s + 2);
    for (int i = 1; i <= n; ++i)
    {
        k[i] = min(k[i], s / w[i]);
        lst[w[i]].eb(v[i], k[i]);
    }
    vector <pii> best;
    for (int i = 1; i <= s; ++i)
    {
        sort(lst[i].rbegin(), lst[i].rend());
        ll need = s / i;
        for (auto &[val, cnt] : lst[i])
        {
            cnt = min(cnt, need);
            int use = 1;
            for (; use <= cnt; use <<= 1)
            {
                best.eb(val * use, 1ll * i * use);
                cnt -= use;
                need -= use;
            }
            if (need && cnt)
            {
                best.eb(val * cnt, 1ll * i * cnt);
                need -= cnt;
                cnt = 0;
            }
        }
    }
    vector <ll> dp(s + 2, 0);
    for (auto &[val, weight] : best)
        for (int j = s; j >= weight; --j)
            dp[j] = max(dp[j], dp[j - weight] + val);
    cout << dp[s];
    exit(0);
}
int main()
{
    if (ifstream(task".inp")) nx
    fast
    cin >> s >> n;
    for (int i = 1; i <= n; ++i)
        cin >> v[i] >> w[i] >> k[i],
        mxk = max(mxk, k[i]);
    if (n == 1) return cout << 1ll * v[1] * min(s / w[1], k[1]), 0;
    if (n <= 100 && mxk <= 10) sub23();
    sub45();
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:7:20: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    7 | #define nx freopen (task".inp","r",stdin), freopen (task".out","w",stdout);
      |            ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:68:31: note: in expansion of macro 'nx'
   68 |     if (ifstream(task".inp")) nx
      |                               ^~
knapsack.cpp:7:52: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
    7 | #define nx freopen (task".inp","r",stdin), freopen (task".out","w",stdout);
      |                                            ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:68:31: note: in expansion of macro 'nx'
   68 |     if (ifstream(task".inp")) nx
      |                               ^~

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