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

Code mẫu của ladpro98

#include <bits/stdc++.h>

using namespace std;

const int N = 1003;
const int MOD = 1e9 + 7;

int dp[N][N];

void add(int &a, int b) {
    a += b;
    if (a >= MOD) a -= MOD;
}

int solve(int n, int k, int m) {
    if (n % m) return 0;
    memset(dp, 0, sizeof(dp));
    dp[0][0] = 1;
    for (int i = 0; i < n; ++i) for (int j = 0; j <= n; ++j) if (dp[i][j]) {
        if (j == 0)
            add(dp[i + 1][m - 1], 1LL * dp[i][j] * k % MOD);
        else {
            add(dp[i + 1][j - 1], dp[i][j]);
            if (j + m - 1 <= n)
                add(dp[i + 1][j + m - 1], 1LL * dp[i][j] * (k - 1) % MOD);
        }
    }
    return dp[n][0];
}

int main() {
    int nTest; cin >> nTest;
    while (nTest--) {
        int n, k, m; cin >> n >> k >> m;
        cout << solve(n, k, m) << endl;
    }
    return 0;
}

Code mẫu của RR

#include <bits/stdc++.h>

#define FOR(i,a,b) for(int i=(a),_b=(b); i<=_b; i++)
#define FORD(i,a,b) for(int i=(a),_b=(b); i>=_b; i--)
#define REP(i,a) for(int i=0,_a=(a); i<_a; i++)
using namespace std;

const int MN = 1011;
const int MOD = 1000000007;

void update(int &x, int val) {
    x += val;
    if (x >= MOD) x -= MOD;
}

int f[1011][1011];

int main() {
    ios :: sync_with_stdio(false);
    int ntest; cin >> ntest;
    while (ntest--) {
        int n, k, m; cin >> n >> k >> m;
        memset(f, 0, sizeof f);
        f[0][0] = 1;
        FOR(i,0,n-1) FOR(bad,0,n) if (f[i][bad]) {
            if (bad) update(f[i+1][bad-1], f[i][bad]);
            if (bad+m-1 <= n) {
                update(f[i+1][bad+m-1], f[i][bad] * (k-1LL) % MOD);
                if (!bad) update(f[i+1][bad+m-1], f[i][bad]);
            }
        }
        cout << f[n][0] % MOD << endl;
    }
    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 ll mod = (ll) (1e9 + 7 + eps);
#define ok puts("ok")
#define maxn 1005
#define maxe 40005

int test, n, m, k;
ll f[maxn][maxn];

int main(){
//  freopen("in.txt", "r", stdin);

    cin >> test;

    Rep(itest, test){
        cin >> n >> k >> m;
        ms(f, 0);
        f[m][m] = k;
        for(int i = m + m; i <= n; i += m){
            ll runh = 0, runl = 0;
            For(j, m, i){
//              cout << i << " " << j << " " << runh << " " << runl << endl;
                if(j == i) f[i][j] = (runh * (k - 1) + runl * (k)) % mod;
                else f[i][j] = (runh * (k - 1) + runl * (k - 1)) % mod;
                runl = (runl + f[i - m][j + 1 - m]) % mod;
                runh = (runh + f[i - m][j] - f[i - m][j - m + 1] + mod) % mod;
            }
        }

        ll res = 0;
        For(i, 1, n) {
            res = (res + f[n][i]) % mod;
        }
        cout << res << endl;
    }

    return 0;

}