Submission #1253404

#	Time	Username	Problem	Language	Result	Execution time	Memory
1253404		thanhcodedao	Knapsack (NOI18_knapsack)	C++17	100 / 100	35 ms	5192 KiB

knapsack

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

#define F first
#define S second
#define pb push_back
#define checkbit(mask,i) ((mask>>i)&1)
#define bit(i) (1<<i)
#define MLog 21
typedef long long ll;
const ll maxN = 1e5+3, modd = 1e9+7;
struct Point {
    ll x,y;
};
ll cross(Point p,Point q,Point r) { // vi tri r voi duong pq >0 la ben trai, =0 la thang hang
    ll val = (q.x-p.x)*(r.y-q.y) - (q.y-p.y)*(r.x-q.x);
    if(val < 0) return -1;
    if(val > 0) return 1;
    return 0;
}
ll dot(Point vecA,Point vecB) { // tra ve >0 la nhon, <0 la tu, =0 la vuong, 2 vecto phai chung goc
    ll val = vecA.x*vecB.x + vecA.y*vecB.y;
    if(val < 0) return -1;
    if(val > 0) return 1;
    return 0;
}
double triarea(Point p,Point q,Point r) { // cross(pq * pr) / 2
    double cross = (q.x-p.x)*(r.y-q.y) - (q.y-p.y)*(r.x-q.x);
    return fabs(cross)/2.0;
}
ll f[2003];
int s,n;
ll v[maxN], w[maxN],k[maxN];
// knapsack vo han su dung nhi phan hoa de toi uu, dpt n*log2(k)*s (co the giam nhieu vi s >= k*w)
void sub1234() {
    for(int i = 1; i<=n; i++) {
        for(int j = 1; k[i] > 0; j <<= 1) {
            ll get = min(k[i],1ll*j); // vd 4 thi sau khi lay 2^0 va 2^1 van con 2^0 co the lay
            k[i] -= get;
            ll val = get * v[i], cost = get * w[i];
            for(int x = s; x>=cost; x--) {
                f[x] = max(f[x],f[x-cost] + val);
            }
        }
    }
    ll ans = 0;
    for(int i = 1; i<=s; i++) ans = max(ans,f[i]);
    cout << ans;
}
vector<pair<ll,ll>> sameW[2003];
void solve() {
    cin >> s >> n;
    for(int i = 1; i<=n; i++) {
        cin >> v[i] >> w[i] >> k[i];
        sameW[w[i]].pb({v[i],k[i]});
    }
    for(int w = s; w>=1; w--) {
        sort(sameW[w].begin(),sameW[w].end(),greater<pair<ll,ll>>());
        vector<ll> firstk(s / w + 5);
        firstk[0] = 0;
        int cnt = 0;
        for(pair<ll,ll> item : sameW[w]) {
            for(int j = 1; j<=item.S; j++) {
                ++cnt;
                if(cnt * w > s) break;
                firstk[cnt] = firstk[cnt-1] + item.F;
            }
        }
        for(int x = s; x>=0; x--) { // n log2 n
            for(int j = 1; j*w <= x; j++) {
                f[x] = max(f[x],f[x - j*w] + firstk[j]);
            }
        }
    }
    ll ans = 0;
    for(int i = 1;i<=s;i++) ans = max(ans,f[i]);
    cout << ans;
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0), cout.tie(0);
    //freopen("inp.txt","r",stdin);
    //freopen("out.txt","w",stdout);
    solve();
    return 0;
}

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