Submission #887772

#	Time	Username	Problem	Language	Result	Execution time	Memory
887772		conthoanco	Knapsack (NOI18_knapsack)	C++14	37 / 100	3 ms	348 KiB

knapsack

#include <bits/stdc++.h>
using namespace std;
#define fi first
#define se second
#define II pair < int , int >
#define pb push_back
#define mset(a , b) memset(a , b , sizeof a)
#define all(a) (a).begin() , (a).end()
const int N = 1e5 + 5;
int s, n, v[N], w[N], k[N], dp[2][N];
deque<II> dq;
void input()
{
    cin >> s >> n;
    for(int i = 1; i <= n; ++i) {
        cin >> v[i] >> w[i] >> k[i];
    }
}
void solve()
{
    int res = 0;
    for(int i = 1; i <= n; ++i) {
        int id = i % 2;
        for(int r = 0; r < w[i]; ++r) {
            while(!dq.empty()) dq.pop_back();
            for(int curS = r; curS <= s; curS += w[i]) {
                II curV = {dp[1 - id][curS] - (curS / w[i]) * v[i], curS};
                while(!dq.empty() && dq.front().fi <= curV.fi) dq.pop_front();
                while(!dq.empty() && dq.back().se < curS - k[i] * w[i]) dq.pop_back();
                dq.push_front(curV);

                int preS = dq.back().se;
//                for(int preS = curS; preS >= 0; preS -= w[i])
                dp[id][curS] = dp[1 - id][preS] + v[i] * (curS - preS) / w[i];
                res = max(res, dp[id][curS]);
            }
        }
    }
    cout << res;
}
int main()
{
    if(fopen("trash.inp" , "r"))
        freopen("trash.inp" , "r" , stdin) , freopen("trash.out" , "w" , stdout);
    // else freopen(".inp" , "r" , stdin) , freopen(".out" , "w" , stdout);
    ios::sync_with_stdio(0);
    cin.tie(0);
    input();
    solve();
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:44:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |         freopen("trash.inp" , "r" , stdin) , freopen("trash.out" , "w" , stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:44:53: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   44 |         freopen("trash.inp" , "r" , stdin) , freopen("trash.out" , "w" , stdout);
      |                                              ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~

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