Submission #651692

#	Time	Username	Problem	Language	Result	Execution time	Memory
651692		marche	Knapsack (NOI18_knapsack)	C++17	100 / 100	296 ms	145284 KiB

knapsack

#include <bits/stdc++.h>
#pragma GCC optimize("O2")
using namespace std;

using ll = long long;

using vi = vector<int>;
#define pb push_back
#define all(x) begin(x), end(x)
#define sz(x) (int) (x).size()

using pi = pair<int,int>;
#define fr first
#define sc second
#define mp make_pair

void setIO(string name = "") {
	cin.tie(0)->sync_with_stdio(0); // see /general/fast-io
	if (sz(name)) {
		freopen((name + ".in").c_str(), "r", stdin); // see /general/input-output
		freopen((name + ".out").c_str(), "w", stdout);
	}
}

int inf = 1000000;
int MOD = 1e9 + 7;
int main() {
	setIO();
    int s,n;
    cin >> s >> n;
    vector<vector<int>>a(n, vector<int>(3));
    for (int i =0 ; i<n; i++){
        for (int j = 0; j<3; j++)cin >> a[i][j];
    }
    unordered_map<int,int>weight;
    function<bool(vector<int>a, vector<int>b)>sr = [&](vector<int>a,vector<int>b){
        if (a[1] < b[1])return true;
        else if (a[1] > b[1])return false;
        else{
            return a[0] > b[0];
        }
    };
    sort(a.begin(), a.end(), sr);
    vector<int>weights;
    vector<int>vals;
    for (int i = 0; i<n; i++){
        int S = s/a[i][1] + 1;
        int togo = S - weight[a[i][1]];
        if (togo <= 0)continue;
        int pushed = 0;
        for (int j = 0; j<min(togo,a[i][2]); j++){
            weights.pb(a[i][1]);
            vals.pb(a[i][0]);
            pushed++;
        }
        weight[a[i][1]]+=pushed;
    }
    int dp[weights.size()+1][2001];
    memset(dp, 0, sizeof(dp));
    for (int i = 1; i<=weights.size(); i++){
        int w = weights[i - 1];
        int v = vals[i - 1];
        for (int j = 1; 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[weights.size()][s];
    return 0;
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:60:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |     for (int i = 1; i<=weights.size(); i++){
      |                     ~^~~~~~~~~~~~~~~~
knapsack.cpp: In function 'void setIO(std::string)':
knapsack.cpp:20:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |   freopen((name + ".in").c_str(), "r", stdin); // see /general/input-output
      |   ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:21:10: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |   freopen((name + ".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