Submission #1268481

#	Time	Username	Problem	Language	Result	Execution time	Memory
1268481		herominhsteve	Knapsack (NOI18_knapsack)	C++20	100 / 100	39 ms	2884 KiB

knapsack

#include <bits/stdc++.h>
#define el '\n'
#define FNAME "NAME"
#define allof(x) x.begin(),x.end()
#define allof1(x) x.begin()+1,x.end()
#define mset(x,n) memset(x,(n),sizeof(x))
using namespace std;
const long long MOD = (long long) 1e9+7;
template<class X,class Y> bool minimize(X &a,Y b){ if (a>b) {a=b; return true;} return false;}
template<class X,class Y> bool maximize(X &a,Y b){ if (a<b) {a=b; return true;} return false;}

void setup(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
	if (fopen(FNAME".inp","r")){
		freopen(FNAME".inp","r",stdin);
		freopen(FNAME".out","w",stdout);
	}
}

const int MAXN = 2001;

struct Goods{
    int maxTake;
    long long val;
    Goods(): val(0), maxTake(0) {}
    Goods(long long V,int t) : val(V), maxTake(t) {}
    bool operator < (const Goods &other) const{
        return (val > other.val or (val==other.val and maxTake > other.maxTake));
    }
};

int W,n;
vector<Goods> goodsByW[MAXN];

void init(){
	cin>>W>>n;
    for (int i=0;i<n;i++){
        long long v; int w,maxTake;
        cin>>v>>w>>maxTake;
        goodsByW[w].emplace_back(v,maxTake);
    }
}

void sol(){
	vector<long long> dp(W+1,0);
    for (int w=1;w<=W;w++){
        sort(allof(goodsByW[w]));
        vector<Goods> &curG = goodsByW[w];
        int totalTake=0,cnt=0,ptr=0;
        while (totalTake * w <= W and ptr < (int)curG.size()){
            for (int j=W;j>=w;j--){
                maximize(dp[j],dp[j-w] + curG[ptr].val);
            }
            cnt++;
            totalTake++;
            if (cnt>=curG[ptr].maxTake){
                cnt=0;
                ptr++;
            }
        }
    }
    cout<<dp[W];
}

int main(){
    setup();
    init();
    sol();
}

Compilation message (stderr)

knapsack.cpp: In function 'void setup()':
knapsack.cpp:16:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   16 |                 freopen(FNAME".inp","r",stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:17:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 |                 freopen(FNAME".out","w",stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

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