Submission #1096047

#	Time	Username	Problem	Language	Result	Execution time	Memory
1096047		InvMOD	Knapsack (NOI18_knapsack)	C++14	73 / 100	109 ms	16844 KiB

knapsack

#include <bits/stdc++.h>
using namespace std;

#define fi first
#define se second
#define gcd __gcd
#define siz(v) v.size()
#define pb push_back
#define pi pair<int,int>
#define all(v) (v).begin(), (v).end()
#define compact(v) (v).erase(unique(all(v)), (v).end())
#define FOR(i, a, b) for(int i = (a); i <= (b); i++)
///#define int long long

using ll = long long;
using ld = long double;
using ull = unsigned long long;

template<typename T> bool ckmx(T& a, const T& b){if(a < b) return a = b, true; return false;}
template<typename T> bool ckmn(T& a, const T& b){if(a > b) return a = b, true; return false;}

const int N = 2e3+1;


int S, n;
ll dp[N], answer;
vector<pair<ll,int>> bag;

void process(ll v, ll w){
    assert(w <= S);
    for(int i = S; i >= w; i--){
        if(dp[i-w] != -1) ckmx(dp[i], dp[i-w] + v);
        ckmx(answer, dp[i]);
    }
    return;
}

void solve()
{
    cin >> S >> n;
    for(int i = 1; i <= n; i++){
        ll v,w,k; cin >> v >> w >> k;
        for(int j = 0; j < (32 - __builtin_clz(k)); j++){
            if(k >= (1<<j)){
                k -= (1<<j);
                if(w * (1ll<<j) > S) break;
                bag.push_back(make_pair(-v * (1ll<<j), w * (1ll<<j)));
            }
            else break;
        }
        if(k){
            if(w * k > S) continue;
            bag.push_back(make_pair(-v * k, w * k));
        }
    }

    sort(bag.begin(), bag.end());
    fill(dp+1, dp+1+S, -1);

    for(int i = 0; (i < min((int)bag.size(), S*2)); i++){
        process(-bag[i].first, bag[i].second);
    }

    cout << answer <<"\n";
}

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    #define name "InvMOD"
    if(fopen(name".INP", "r")){
        freopen(name".INP","r",stdin);
        freopen(name".OUT","w",stdout);
    }

    int t = 1; //cin >> t;
    while(t--) solve();
    return 0;
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:75:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |         freopen(name".INP","r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:76:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |         freopen(name".OUT","w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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