Submission #659039

#	Time	Username	Problem	Language	Result	Execution time	Memory
659039		NONTAC	Knapsack (NOI18_knapsack)	C++11	29 / 100	8 ms	15664 KiB

knapsack

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

struct item
{
    int v, w;
};

int n, s;
item a[100005];
int k[100005];
int dem[20005];
vector<item> b;
long long dp[20005][2005];

bool cmp(item &a, item &b)
{
    if(a.w == b.w) return a.v > b.v;
    return a.w < b.w;
}

int main()
{
    //freopen("test.in","r",stdin);
    //freopen("test.out","w",stdout);

    cin>>s>>n;

    for(int i = 0; i < n; i++){
        cin>>a[i].v>>a[i].w>>k[i];
        if(k[i] > s / a[i].w) k[i] = s / a[i].w;
    }
    sort(a, a + n, cmp);

    //for(int i = 0; i < n; i++) cout<<a[i].v<<" "<<a[i].w<<" "<<a[i].k<<endl;

    for(int i = 1; i <= 2000; i++) dem[i] = (2000 / i);

    int cnt = 0;
    b.push_back({0, 0});
    for(int i = 0; i < n; i++){
        int d = k[i], w = a[i].w;
        if(dem[w] <= 0) continue;
        if(d >= dem[w]){
            while(dem[w]--) b.push_back({a[i].v, a[i].w});
        }
        else{
            dem[w] -= d;
            while(d--) b.push_back({a[i].v, a[i].w});
        }
    }

    //print();
    //for(int i = 0; i < b.size(); i++) cout<<b[i].w<<" "<<b[i].v<<endl;

    for(int i = 1; i < b.size(); i++){
        long long v = b[i].v, w = b[i].w;
        for(int j = 0; j <= s; j++){
            dp[i][j] = dp[i - 1][j];
            if(j - w >= 0) dp[i][j] = max(dp[i][j], dp[i - 1][j - w] + v);
        }
    }

    cout<<dp[b.size() - 1][s];

    return 0;
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:56:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<item>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   56 |     for(int i = 1; i < b.size(); i++){
      |                    ~~^~~~~~~~~~
knapsack.cpp:39:9: warning: unused variable 'cnt' [-Wunused-variable]
   39 |     int cnt = 0;
      |         ^~~

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