Submission #593610

#	Time	Username	Problem	Language	Result	Execution time	Memory
593610		wyhong3103	Knapsack (NOI18_knapsack)	C++14	29 / 100	2 ms	340 KiB

knapsack

#include <bits/stdc++.h>
#include <bits/stdc++.h>
#define all(x) begin(x),end(x)
#define fir first
#define sec second
#define sz(x) x.size()
#define pb push_back
 
using namespace std;
using vi = vector<int>;
using pi = pair<int,int>;
using pdb = pair<double,double>;
using ll = long long;
using pll = pair<ll,ll>;
const double EPS = (1e-7);
 
void setio(string s){
	freopen((s + ".in").c_str(),"r",stdin);
	freopen((s + ".out").c_str(),"w",stdout);
}
 
const int MXN = 1e5 + 5;
const int MXS = 2005;
//{val, k used}
pll dp[MXS];
pll dp1[MXS];

struct Item{
    int v, w, k;
};

void solve(){
    int n, s;
    cin >> s >> n;
    
    vector<Item> items(n);
    for(auto& i : items) cin >> i.v >> i.w >> i.k;

    for(int i{}; i < n; i++){
        for(int j{1}; j <= s; j++){
            //based on last
            if (dp[j].fir > dp1[j].fir){
                dp1[j].fir = dp[j].fir;
                dp1[j].sec = 0;
            }
            if (j-items[i].w >= 0 && dp[j-items[i].w].fir + items[i].v > dp1[j].fir){
                dp1[j].fir = dp[j-items[i].w].fir + items[i].v; 
                dp1[j].sec = 1;
            }

            //based on cur
            if (j-items[i].w >= 0 && dp1[j-items[i].w].fir + items[i].v > dp1[j].fir && dp1[j-items[i].w].sec + 1 <= items[i].k){
                dp1[j].fir = dp1[j-items[i].w].fir + items[i].v; 
                dp1[j].sec = dp1[j-items[i].w].sec + 1;
            }
            if (dp1[j-1].fir > dp1[j].fir){
                dp1[j].fir = dp1[j-1].fir;
                dp1[j].sec = dp1[j-1].sec;
            }
        }
        for(int j{1}; j <= s; j++){
            dp[j] = dp1[j];
            dp1[j] = {};
        } 
    }

    cout << dp[s].fir;
} 
 
int main(){
    ios_base::sync_with_stdio(false);
    cin.tie(nullptr);
    int t = 1;
    while(t--){
        solve();
    }
	return 0;
}

Compilation message (stderr)

knapsack.cpp: In function 'void setio(std::string)':
knapsack.cpp:18:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   18 |  freopen((s + ".in").c_str(),"r",stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:19:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   19 |  freopen((s + ".out").c_str(),"w",stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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