Lưu ý: Các code mẫu dưới đây chỉ mang tính tham khảo và có thể không AC được bài tập này

Code mẫu của flashmt

#include <iostream>
#include <algorithm>
#define oo 2147483647
using namespace std;

int n,m,a[101],cur[101],ans[100100]={1};

int main()
{
    cin >> n >> m;
    for (int i=0;i<n;i++) cin >> a[i];
    for (int i=1;i<=m;i++)
    {
        ans[i]=oo;
        for (int j=0;j<n;j++)
        {
            if (1LL*a[j]*ans[cur[j]]<=ans[i-1]) cur[j]++;
            if (oo/a[j]>=ans[cur[j]]) ans[i]=min(ans[i],a[j]*ans[cur[j]]);
        }
    }
    cout << ans[m] << endl;
}

Code mẫu của ladpro98

#include <iostream>
#include <cstdio>
#include <algorithm>
#include <climits>
const int N = 100005;
const int K = 110;
const int oo = 1000000009;
using namespace std;
int p[K], pos[K];
int F[N];
int k, n;

int main() {
    cin >> k >> n;
    for(int i = 1; i <= k; i++)
        cin >> p[i];
    sort(p + 1, p + 1 + k);
    F[0] = 1;
    for(int i = 1; i <= k; i++)
        pos[i] = 0;
    for(int i = 1; i <= n; i++) {
        F[i] = INT_MAX;
        for(int j = 1; j <= k; j++) {
            while (F[pos[j]] * p[j] <= F[i - 1]) pos[j]++;
            F[i] = min(F[i], F[pos[j]] * p[j]);
        }
    }
    cout << F[n];
    return 0;   
}

Code mẫu của RR

#include <iostream>
#include <algorithm>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <string>
#include <vector>
#include <queue>
#include <stack>
#include <map>
#include <set>
#include <iomanip>
#include <bitset>
#include <complex>

#define FOR(i,a,b) for(int i = a; i <= b; ++i)
#define FORD(i,a,b) for(int i = a; i >= b; --i)
#define REP(i,a) for(int i = 0; i < a; ++i)
#define MP make_pair
#define PB push_back
#define F first
#define S second
using namespace std;

int n, k, a[111];
set< pair<int,int> > s;

int main() {
    scanf("%d%d", &n, &k);
    FOR(i,1,n) scanf("%d", &a[i]);
    sort(a+1, a+n+1);
    FOR(i,1,n) s.insert(MP(a[i], i));

    FOR(i,1,k) {
        int u = s.begin()->F, last = s.begin()->S; s.erase(s.begin());
        if (i == k) {
            cout << u << endl;
            break;
        }
        // Add candidates
        int gh;
        if (s.empty()) gh = 2000111000;
        else {
            set< pair<int,int> > :: iterator it = s.end(); --it;
            gh = it->F;
        }

        FOR(j,last,n) {
            if (u > 2000111000 / a[j]) break;
            if (s.size() == k-i+1 && u * a[j] >= gh) break;
            s.insert(MP(u * a[j], j));
            if (s.size() > k-i+1) {
                set< pair<int,int> > :: iterator it = s.end(); --it;
                s.erase(it);
            }
        }
    }
    return 0;
}

Code mẫu của hieult

#include <set>
#include <map>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <string>
#include <vector>
#include <cstdlib>
#include <cstring>
#include <sstream>
#include <iomanip>
#include <iostream>
#include <algorithm>
#include <ctime>
#include <deque>
#include <bitset>
#include <cctype>
#include <utility>

using namespace std;

typedef long long ll;
typedef long double ld;
typedef unsigned int ui;
typedef unsigned long long ull;

#define Rep(i,n) for(int i = 0; i < (n); ++i)
#define Repd(i,n) for(int i = (n)-1; i >= 0; --i)
#define For(i,a,b) for(int i = (a); i <= (b); ++i)
#define Ford(i,a,b) for(int i = (a); i >= (b); --i)
#define Fit(i,v) for(__typeof((v).begin()) i = (v).begin(); i != (v).end(); ++i)
#define Fitd(i,v) for(__typeof((v).rbegin()) i = (v).rbegin(); i != (v).rend(); ++i)
#define mp make_pair
#define pb push_back
#define fi first
#define se second
#define sz(a) ((int)(a).size())
#define all(a) (a).begin(), (a).end()
#define ms(a,x) memset(a, x, sizeof(a))

template<class F, class T> T convert(F a, int p = -1) {
    stringstream ss;
    if (p >= 0)
        ss << fixed << setprecision(p);
    ss << a;
    T r;
    ss >> r;
    return r;
}
template<class T> T gcd(T a, T b) {
    T r;
    while (b != 0) {
        r = a % b;
        a = b;
        b = r;
    }
    return a;
}
template<class T> T lcm(T a, T b) {
    return a / gcd(a, b) * b;
}
template<class T> T sqr(T x) {
    return x * x;
}
template<class T> T cube(T x) {
    return x * x * x;
}
template<class T> int getbit(T s, int i) {
    return (s >> i) & 1;
}
template<class T> T onbit(T s, int i) {
    return s | (T(1) << i);
}
template<class T> T offbit(T s, int i) {
    return s & (~(T(1) << i));
}
template<class T> int cntbit(T s) {
    return s == 0 ? 0 : cntbit(s >> 1) + (s & 1);
}

const int bfsz = 1 << 16;
char bf[bfsz + 5];
int rsz = 0;
int ptr = 0;
char gc() {
    if (rsz <= 0) {
        ptr = 0;
        rsz = (int) fread(bf, 1, bfsz, stdin);
        if (rsz <= 0)
            return EOF;
    }
    --rsz;
    return bf[ptr++];
}
void ga(char &c) {
    c = EOF;
    while (!isalpha(c))
        c = gc();
}
int gs(char s[]) {
    int l = 0;
    char c = gc();
    while (isspace(c))
        c = gc();
    while (c != EOF && !isspace(c)) {
        s[l++] = c;
        c = gc();
    }
    s[l] = '\0';
    return l;
}
template<class T> bool gi(T &v) {
    v = 0;
    char c = gc();
    while (c != EOF && c != '-' && !isdigit(c))
        c = gc();
    if (c == EOF)
        return false;
    bool neg = c == '-';
    if (neg)
        c = gc();
    while (isdigit(c)) {
        v = v * 10 + c - '0';
        c = gc();
    }
    if (neg)
        v = -v;
    return true;
}

typedef pair<int, int> II;
const ld PI = acos(-1.0);
const ld eps = 1e-9;
const int dr[] = { -1, 0, +1, 0};
const int dc[] = { 0, +1, 0, -1};
const int inf = (int) 1e9 + 5;
const ll linf = (ll) 1e16 + 5;
const int mod = (ll) (1e9 + 7 + eps);
#define ok puts("ok")
#define maxn 100005

int a[maxn], vt[maxn];
ll q[maxn];
int n, x;

int main(){
//  freopen("in.txt", "r", stdin);
    scanf("%d %d", &n, &x);
    For(i, 1, n) scanf("%d", &a[i]);
    sort(a + 1, a + n + 1);

    q[0] = 1;
    ms(vt, 0);
    For(run, 1, x){
        ll MIN = linf;
        For(i, 1, n) {
            while(a[i] * q[vt[i]] <= q[run - 1]) vt[i]++;
            MIN = min(MIN, a[i] * q[vt[i]]);
        }
        q[run] = MIN;
    }

    cout << q[x] << endl;

}