Submission #710814

#	Time	Username	Problem	Language	Result	Execution time	Memory
710814		vjudge1	Knapsack (NOI18_knapsack)	C++17	100 / 100	85 ms	33160 KiB

knapsack

/*
                                    بسم الله الرحمن الرحيم
                وَاتَّقُوا يَوْمًا تُرْجَعُونَ فِيهِ إِلَى اللَّهِ ۖ ثُمَّ تُوَفَّىٰ كُلُّ نَفْسٍ مَّا كَسَبَتْ وَهُمْ لَا يُظْلَمُونَ
                                In The name if allah
                And fear a Day when you will be returned to Allah
                Then every soul will be compensated for what it earned
                      and they will not be treated unjustly.
*/
#include <bits/stdc++.h>

using namespace std;

#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>

using namespace __gnu_pbds;

#define ordered_set tree<long long , null_type,less<long long >, rb_tree_tag,tree_order_statistics_node_update>

void init() {
    cin.tie(nullptr);
    std::istream::sync_with_stdio(false);
    cout.tie(nullptr);
    std::ostream::sync_with_stdio(false);
}

const long long mod = 1e9 + 7;
vector<pair<int, int>> vec[2001];
long long dp[2001][2001];
long long n, s;

long long solve(int i, int w) {
    if (w == 0)
        return w;
    if (i > w)
        return 0;
    long long &ret = dp[i][w];
    if (~ret)
        return ret;
    ret = solve(i + 1, w);
    bool is = true;
    long long ans = 0, tot = 0;
    for (int j = 0; j < vec[i].size(); ++j) {
        for (int k = 1; k <= vec[i][j].second; ++k) {
            ans += vec[i][j].first;
            tot += i;
            if (w >= tot)
                ret = max(ret, solve(i + 1, w - tot) + ans);
            else {
                is = false;
                break;
            }
        }
        if (!is)
            break;
    }
    return ret;
}

int main() {
    init();
    cin >> s >> n;

    int w, v, k;
    for (int i = 0; i < n; ++i) {
        cin >> v >> w >> k;
        vec[w].emplace_back(v, k);
    }
    for (int i = 1; i <= s; ++i)
        sort(vec[i].begin(), vec[i].end(), greater<pair<int, int >>());

    for (int i = 1; i <= s; ++i) {
        for (int j = 1; j <= s; ++j) {
            dp[i][j] = max(dp[i][j], dp[i - 1][j]);
            long long ans = 0, tot = 0;
            for (int l = 0; l < vec[i].size(); ++l) {
                for (int k = 0; k < vec[i][l].second; ++k) {
                    ans += vec[i][l].first;
                    tot += i;
                    if (j >= tot)
                        dp[i][j] = max(dp[i][j], dp[i - 1][j - tot] + ans);
                    if (tot > j)
                        break;
                }
                if (tot > j)
                    break;
            }
        }
    }
    cout << dp[s][s];
}

Compilation message (stderr)

knapsack.cpp: In function 'long long int solve(int, int)':
knapsack.cpp:43:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   43 |     for (int j = 0; j < vec[i].size(); ++j) {
      |                     ~~^~~~~~~~~~~~~~~
knapsack.cpp: In function 'int main()':
knapsack.cpp:76:31: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |             for (int l = 0; l < vec[i].size(); ++l) {
      |                             ~~^~~~~~~~~~~~~~~

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