Submission #914300

#	Time	Username	Problem	Language	Result	Execution time	Memory
914300		May27_th	Knapsack (NOI18_knapsack)	C++17	100 / 100	63 ms	52356 KiB

knapsack

#include <bits/stdc++.h>
#define int64_t long long
#define double long double
using namespace std;
using type = int64_t;
const long long mod = 998244353, inf = 1e18;
const int base = 33;
const int N = 2e5 + 10;
const int LG = 20;

int dx[] = {1, -1, 0, 0};
int dy[] = {0, 0, 1, -1};

void Minimize(int64_t &a, int64_t b) {if(b < a) a = b;}
void Maximize(int64_t &a, int64_t b) {if(b > a) a = b;}
void Add(int64_t& a, int64_t b) {a = a + b; a %= mod;}
void Dec(int64_t& a, int64_t b) {a = a - b + mod; a %= mod;}

int S, n; vector<pair<int64_t, int64_t>>items[3000]; int64_t f[3000][3000];
void Solve(void)
{
    /**
        item: v, w, k;
        sort theo weight: 1 <= w <= S
        voi moi weight chon toi da S/w thang gia tri nhat
        f[i][j] la dung den cac thg weight i va dang co space j
        f[i][j] = f[i - 1][j - w * t] + v * t;
    **/
    cin >> S >> n;
    for(int i = 1; i <= n; i ++){
        int64_t v, w, k; cin >> v >> w >> k;
        items[w].push_back(make_pair(v, k));
    }
    for(int i = 1; i <= S; i ++){
        for(int j = 0; j <= S; j ++){
            f[i][j] = -inf;
        }
    }
    f[0][0] = 0;
    for(int i = 1; i <= S; i ++){
        for(int j = 0; j <= S; j ++){
            f[i][j] = f[i - 1][j];
        }
        int sz = items[i].size();
        if(sz > 0){
            sort(items[i].rbegin(), items[i].rend());
            for(int j = 0; j <= S; j ++){
                int64_t tot = 0;
                int64_t take = 0, have = 0;
                int pos = 0;
                while((take + 1) * i <= j && pos < sz){
                    take ++;
                    tot += items[i][pos].first;
                    if(f[i - 1][j - take * i] != -inf){
                        Maximize(f[i][j], f[i - 1][j - take * i] + tot);
                    }
                    have ++;
                    if(have == items[i][pos].second){
                        have = 0;
                        pos ++;
                    }
                }
            }
        }
    }
    cout << f[S][S];

}

int main()
{
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    if(fopen("time.in", "r")){
        freopen("time.in", "r", stdin);
        freopen("time.out", "w", stdout);
    }
    if(fopen("A.inp", "r")){
        freopen("A.inp", "r", stdin);
        freopen("A.out", "w", stdout);
    }
    int tc = 1;
    //cin >> tc;
    while(tc --){
        Solve();
    }
}

Compilation message (stderr)

knapsack.cpp: In function 'int main()':
knapsack.cpp:75:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |         freopen("time.in", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:76:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |         freopen("time.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:79:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   79 |         freopen("A.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
knapsack.cpp:80:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   80 |         freopen("A.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

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