Submission #658974

#	Time	Username	Problem	Language	Result	Execution time	Memory
658974		NONTAC	Knapsack (NOI18_knapsack)	C++11	0 / 100	1 ms	340 KiB

knapsack

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

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

int n, s;
item a[100001];
vector<item> b;
int dp[15520][2001];
vector<map<int, int, greater<int> > > lis(2001);

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

void print()
{
    for(int i = 1; i < lis.size(); i++){
        cout<<"Weight "<<i<<": "<<endl;
        for(auto x : lis[i]){
            cout<<x.first<<" "<<x.second<<endl;
        }
        cout<<endl;
    }
}

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;
    }
    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, wei = a[0].w;
    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;
                cnt += a[i].k;
            }
            else{
                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();

    b.push_back({0, 0, 0});
    for(int i = 1; i < lis.size(); i++){
        for(auto x : lis[i]){
            int t = x.second;
            while(t--){
                item tmp = {x.first, i, 1};
                b.push_back(tmp);
            }
        }
    }

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

    for(int i = 1; i < b.size(); i++){
        int 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 'void print()':
knapsack.cpp:23:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::map<int, int, std::greater<int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |     for(int i = 1; i < lis.size(); i++){
      |                    ~~^~~~~~~~~~~~
knapsack.cpp: In function 'int main()':
knapsack.cpp:64:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::map<int, int, std::greater<int> > >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |     for(int i = 1; i < lis.size(); i++){
      |                    ~~^~~~~~~~~~~~
knapsack.cpp:76:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<item>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |     for(int i = 1; i < b.size(); i++){
      |                    ~~^~~~~~~~~~
knapsack.cpp:46:18: warning: unused variable 'wei' [-Wunused-variable]
   46 |     int cnt = 0, wei = a[0].w;
      |                  ^~~
knapsack.cpp:34:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   34 |     freopen("test.in","r",stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:35:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   35 |     freopen("test.out","w",stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

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