Submission #1277047

#	Time	Username	Problem	Language	Result	Execution time	Memory
1277047		vibeduck	Knapsack (NOI18_knapsack)	C++20	100 / 100	263 ms	40292 KiB

knapsack

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

#define pb push_back
#define pf push_front
#define mp make_pair
#define fi first
#define se second
#define int long long
#define all(x) (x).begin(), (x).end()

typedef long double ld;
typedef long long ll;
typedef pair<ll,ll> pll;
typedef pair<int,int> pii;
typedef vector<int> vi;
typedef vector<ll> vll;
typedef vector<bool> vb;
typedef vector<vector<int>> vvi;
typedef vector<vector<bool>> vvb;
typedef vector<vector<ll>> vvll;
typedef vector<string> vs;
typedef vector<vector<string>> vvs;
typedef vector<char> vc;
typedef vector<vector<char>> vvc;
typedef map<int, int> mii;
typedef unordered_map<int, int> umii;

const int mod = 1e9 + 7;
const int inf = INTMAX_MAX;
const bool tc = false;

int s, n;
const int mxn = 101, mxs = 2002;
// int v[mxn], w[mxn], k[mxn];
int dp[mxs][mxs]; //mii tmp[mxn];
mii tmp[mxs]; vector<pii> item[mxs];

inline void solve() {
    cin >> s >> n;
    for (int i = 0; i < n; i++) {
        int v, w, k;
        cin >> v >> w >> k;
        k = min(k, (int)2000);
        tmp[w][-v] += k;
    }
    for (int i = 1; i <= s; i++) {
        for (auto &x : tmp[i]) item[i].pb({-x.fi, x.se});
    }

    // for (int i = 1; i <= s; i++) {
    //     if (!item[i].size()) continue;
    //     cout << i << ": \n";
    //     for (auto &x : item[i]) cout << x.fi << " " << x.se << '\n';
    //     cout << '\n';
    // }

    if (item[1].size()) {
        int tkn = 0; int vl = 0; int ptr = 0;
        for (int i = 1; i <= 2000; i++) {
            if (item[1][ptr].se == 0) {
                if (ptr == item[1].size() - 1) break;
                ptr++;
            }
            tkn += 1;
            vl += item[1][ptr].fi;
            item[1][ptr].se--;
            if (tkn > s) break;
            dp[1][s - tkn] = vl;
        }
    }

    // for (int i = 1; i <= s; i++) {
    //     if (!item[i].size()) continue;
    //     cout << i << ": \n";
    //     for (auto &x : item[i]) cout << x.fi << " " << x.se << '\n';
    //     cout << '\n';
    // }

    for (int i = 2; i <= 2000; i++) {
        // i is current weight type
        for (int j = 0; j <= s; j++) {
            // j is how much is left afterwards in knapsack
            int tkn = 0, vl = 0, ptr = 0;
            vector<pii> og = item[i];
            dp[i][j] = dp[i - 1][j];
            if (item[i].size()) {
                // cout << i << " weight with " << j << " left: ";
                for (int nm = 0; nm <= 2000; nm++) {
                    // nm is how many we took of current
                    // cout << item[i][ptr].fi << " " << item[i][ptr].se << " aa: ";
                    if (item[i][ptr].se == 0) {
                        if (ptr == item[i].size() - 1) break;
                        ptr++;
                    }
                    tkn += i;
                    vl += item[i][ptr].fi;
                    item[i][ptr].se--;
                    if (j + tkn > s) break;
                    //cout << j + tkn << " aa\n";
                    dp[i][j] = max(dp[i][j], dp[i - 1][j + tkn] + vl);
                }
                // cout << dp[i][j] << "\n";
            }
            item[i] = og;
        }
    }

    // for (int i = 1; i <= s; i++) {
    //     cout << i << ": ";
    //     for (int j = 0; j <= s; j++) cout << dp[i][j] << " ";
    //     cout << '\n';
    // }

    int ans = 0;
    for (int i = 0; i <= s; i++) ans = max(ans, dp[2000][i]);

    cout << ans << '\n';
}

void setIO(string s) {
    freopen((s + ".in").c_str(), "r", stdin);
    freopen((s + ".out").c_str(), "w", stdout);
}

signed main() {
    ios::sync_with_stdio(false);
    cout.tie(0);
    cin.tie(0);
    //setIO();

    int t = 1;
    if (tc) {
        cin >> t;
    }

    while (t--) {
        solve();
    }
}

Compilation message (stderr)

knapsack.cpp: In function 'void setIO(std::string)':
knapsack.cpp:122:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  122 |     freopen((s + ".in").c_str(), "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:123:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  123 |     freopen((s + ".out").c_str(), "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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