Submission #658987

#	Time	Username	Problem	Language	Result	Execution time	Memory
658987		NONTAC	Knapsack (NOI18_knapsack)	C++11	49 / 100	133 ms	262144 KiB

knapsack

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

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

int n, s;
item a[100002];
vector<item> b;
long long dp[40000][2002];

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>>a[i].k;
        if(a[i].k > s / a[i].w) a[i].k = 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;

    int cnt = 0;
    b.push_back({0, 0, 0});
    for(int i = 0; i < n; i++){
        //if(a[i].w == wei){
            if(s / a[i].w >= cnt + a[i].k){
                //lis[a[i].w][a[i].v] = a[i].k;
                int t = a[i].k;
                while(t-- > 0) b.push_back({a[i].v, a[i].w, 1});
                cnt += a[i].k;
            }
            else{
                int t = s / a[i].w - cnt;
                while(t-- > 0) b.push_back({a[i].v, a[i].w, 1});
                //lis[a[i].w][a[i].v] = s / a[i].w - cnt;
                cnt = 0;
            }
        //}
        if(a[i + 1].w != a[i].w) cnt = 0;
    }

    //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:58:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<item>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   58 |     for(int i = 1; i < b.size(); i++){
      |                    ~~^~~~~~~~~~

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