Submission #768653

#	Time	Username	Problem	Language	Result	Execution time	Memory
768653		mohamedsiu	Knapsack (NOI18_knapsack)	C++14	100 / 100	59 ms	3728 KiB

knapsack

#include<bits/stdc++.h>
//#define int long long
#define pii pair<int,int>
#define fi first
#define se second
using namespace std;
using ll = long long;
const int maxn = 2e3 + 5;
const int maxN = 1e5 + 5;
const int mod = 1e9 + 7;
const int inf = 2e9 + 7;
const int tt = 250;
int dx[] = {0,-1,0,1,-1,1,-1,1};
int dy[] = {-1,0,1,0,-1,1,1,-1};

struct Item
{
    int val;
    int wei;
    int cnt;
};

Item a[maxN];

bool functor(Item p,Item q)
{
    return p.val > q.val;
}

int S,n;

vector<int> vc[maxn];
int dp[2][maxn];

int32_t main()
{
//    freopen("test.inp","r",stdin);
//    freopen("test.out","w",stdout);
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> S >> n;
    for(int i = 1;i <= n;i++)
    {
        cin >> a[i].val >> a[i].wei >> a[i].cnt;
    }

    sort(a + 1,a + n + 1,functor);

    for(int i = 1;i <= n;i++)
    {
        while(vc[a[i].wei].size() < (S/a[i].wei) && a[i].cnt > 0)
        {
            vc[a[i].wei].push_back(a[i].val);
            a[i].cnt--;
        }
    }

    dp[0][0] = 0;

    for(int i = 1;i <= S;i++)
    {
        int now = i%2;
        int pre = 1 - now;
        for(int j = 0;j <= S;j++)
        {
            dp[now][j] = dp[pre][j];
            int cnt = 0;
            int sum = 0;
            for(int k: vc[i])
            {
                cnt++;
                sum += k;
                if(cnt*i > j) break;
                dp[now][j] = max(dp[now][j],dp[pre][j - cnt*i] + sum);
            }
        }
    }

    cout << dp[S%2][S];
}

Compilation message (stderr)

knapsack.cpp: In function 'int32_t main()':
knapsack.cpp:52:35: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   52 |         while(vc[a[i].wei].size() < (S/a[i].wei) && a[i].cnt > 0)
      |               ~~~~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~

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