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>
#include <cstdio>
using namespace std;

long long a[555][555], f[555][555];
int n, k;

int main()
{
    cin >> n >> k;
    for (int i = 1; i <= n; i++)
        for (int j = 1; j <= n; j++)
            scanf("%lld", a[i] + j);

    for (int i = 1; i < n; i++)
        for (int j = n; j > i; j--)
            a[i][j] += a[j][i] - a[i - 1][j + 1] + a[i - 1][j] + a[i][j + 1];

    for (int i = 1; i < n; i++)
        for (int j = 1; j <= k; j++)
            for (int ii = 0; ii < i; ii++)
                f[i][j] = max(f[i][j], f[ii][j - 1] + a[i][i + 1] - a[ii][i + 1]);

    long long ans = 0;
    for (int i = 1; i < n; i++) ans = max(ans, f[i][k]);
    cout << ans << endl;
}

Code mẫu của happyboy99x

#include <iostream>
#include <cassert>
#include <cstring>
#include <cstdio>
using namespace std;

const int N = 500;
long long total[N][N], f[N][N];
int a[N][N], n, special;

template<class T> bool checkMax(T &a, const T &b) {
    return a < b ? a = b, true : false;
}

int main() {
#ifndef ONLINE_JUDGE
    assert(freopen("nsrail.in", "r", stdin));
#endif
    ios::sync_with_stdio(false);
    cin >> n >> special;
    for(int i = 0; i < n; ++i)
        for(int j = 0; j < n; ++j)
            cin >> a[i][j];
    for(int j = 0; j < n; ++j) {
        for(int i = j - 1; i >= 0; --i) {
            total[i][j] = total[i + 1][j];
            for(int k = j; k < n; ++k) total[i][j] += a[i][k] + a[k][i];
        }
    }
    f[0][0] = 0;
    for(int last = 0; last < n; ++last) {
        for(int put = 0; put < special; ++put) if(f[last][put] >= 0) {
            for(int next = last + 1; next < n; ++next) {
                checkMax(f[next][put + 1], f[last][put] + total[last][next]);
            }
        }
    }
    long long res = 0;
    for(int last = 0; last < n; ++last)
        checkMax(res, f[last][special]);
    printf("%lld\n", res);
    return 0;
}

Code mẫu của ladpro98

#include <bits/stdc++.h>

using namespace std;

typedef long long word;

const int N = 505;

int n, k;
word a[N][N], sumCost[N][N], cost[N][N];
word dp[2][N][N];
word temp[N];

void maximize(word &a, word b) { a = a < b ? b : a; }

void genTest() {
    ofstream fout ("NSRAIL.txt");
    int n = 500, k = 200;
    fout << n << ' ' << k << endl;
    srand(time(NULL));
    for (int i = 0; i < n; ++i) {
        for (int j = 0; j < n; ++j) {
            if (i != j)
                fout << rand() % 100000 << ' ';
            else
                fout << "0 ";
        }
        fout << endl;
    }
}

int main() {
    ios::sync_with_stdio(0); cin.tie(0);
#ifndef ONLINE_JUDGE
    genTest();
    freopen("NSRAIL.txt", "r", stdin);
#endif
    cin >> n >> k;
    for (int i = 1; i <= n; ++i) for (int j = 1; j <= n; ++j) {
        cin >> a[i][j];
        sumCost[min(i, j)][max(i, j)] += a[i][j];
        if (i != j) {
            temp[min(i, j)] += a[i][j];
            temp[max(i, j)] -= a[i][j];
        }
    }
    for (int i = 1; i <= n; ++i) for (int j = 1; j <= n; ++j)
        sumCost[i][j] += sumCost[i - 1][j];
    for (int i = 1; i <= n; ++i) temp[i] += temp[i - 1];
    for (int i = 1; i < n; ++i) {
        cost[i][i] = temp[i];
        for (int j = i + 1; j < n; ++j)
            cost[i][j] = cost[i][j - 1] - sumCost[i][j];
    }
    int cur = 0, nxt = 1;
    for (int i = 1; i < n; ++i) {
        for (int j = 0; j <= i && j <= k; ++j) for (int p = 0; p <= i; ++p) dp[nxt][j][p] = 0;
        for (int j = 0; j < i && j <= k; ++j) for (int p = 0; p < i; ++p) {
            maximize(dp[nxt][j][p], dp[cur][j][p]);
            maximize(dp[nxt][j + 1][i], dp[cur][j][p] + cost[i][i] - cost[p][i]);
        }
        cur ^= 1; nxt ^= 1;
    }
    word ans = 0;
    for (int i = 0; i < n; ++i) maximize(ans, dp[cur][k][i]);
    cout << ans << endl;
    return 0;
}

Code mẫu của RR

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

#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++)
#define FORN(i,a,b) for(int i=(a),_b=(b);i<_b;i++)
#define DOWN(i,a,b) for(int i=a,_b=(b);i>=_b;i--)
#define SET(a,v) memset(a,v,sizeof(a))
#define sqr(x) ((x)*(x))
#define ll long long
#define F first
#define S second
#define PB push_back
#define MP make_pair

#define DEBUG(x) cout << #x << " = "; cout << x << endl;
#define PR(a,n) cout << #a << " = "; FOR(_,1,n) cout << a[_] << ' '; cout << endl;
#define PR0(a,n) cout << #a << " = "; REP(_,n) cout << a[_] << ' '; cout << endl;
using namespace std;

//Buffer reading
int INP,AM,REACHEOF;
const int BUFSIZE = (1<<12) + 17;
char BUF[BUFSIZE+1], *inp=BUF;
#define GETCHAR(INP) { \
    if(!*inp && !REACHEOF) { \
        memset(BUF,0,sizeof BUF);\
        int inpzzz = fread(BUF,1,BUFSIZE,stdin);\
        if (inpzzz != BUFSIZE) REACHEOF = true;\
        inp=BUF; \
    } \
    INP=*inp++; \
}
#define DIG(a) (((a)>='0')&&((a)<='9'))
#define GN(j) { \
    AM=0;\
    GETCHAR(INP); while(!DIG(INP) && INP!='-') GETCHAR(INP);\
    if (INP=='-') {AM=1;GETCHAR(INP);} \
    j=INP-'0'; GETCHAR(INP); \
    while(DIG(INP)){j=10*j+(INP-'0');GETCHAR(INP);} \
    if (AM) j=-j;\
}
//End of buffer reading

const long double PI = acos((long double) -1.0);

int n, k;
int a[511][511];
long long sum[511][511], f[511][511];

int main() {
    while (scanf("%d%d", &n, &k) == 2) {
        FOR(i,1,n) FOR(j,1,n) {
            scanf("%d", &a[i][j]);
        }
        FOR(i,1,n) FOR(j,i+1,n) a[i][j] += a[j][i];

        memset(sum, 0, sizeof sum);
        memset(f, 0, sizeof f);

        FORD(j,n,1) FOR(i,j,n) {
            sum[j][i] = sum[j+1][i];
            FOR(x,i+1,n)
                sum[j][i] += a[j][x];
        }

        long long res = 0;
        FOR(i,1,n-1) FOR(x,1,k) {
            FOR(j,0,i-1)
                f[i][x] = max(f[i][x], f[j][x-1] + sum[j+1][i]);
            res = max(res, f[i][x]);
        }
        cout << res << 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>
#include <cassert>

using namespace std;

typedef long long ll;
typedef 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[] = {0, +1, 0, -1};
const int dc[] = {+1, 0, -1, 0};

const int inf = (int)1e9 + 5;
const ll linf = (ll)1e16 + 5;
//const ll mod = (ll)1e9 + 7;

#define maxn 505

ll f[505][505], l[505][505];
int  a[505][505], d[505][505], c[505];
int n, num;

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

    ms(d, 0); ms(f, 0); ms(c, 0); ms(l, 0);
    gi(n); gi(num);
    For(i, 1, n) {
        For(j, 1, n){
            gi(a[i][j]);
            if(j < i){
                a[j][i] += a[i][j];
                a[i][j] = 0;
            }
        }
    }

    For(i, 1, n) For(j, i + 1, n){
        a[i][j - 1] = a[i][j];
    }
    n--;

    For(i, 1, n) For(j, i, n) d[i][j] = d[i][j - 1] + a[i][j];

    For(i, 1, n){
        For(j, 1, i) c[i] += a[j][i];
    }

    For(i, 1, n){
        l[1][i] = d[1][i];
        For(j, 2, i) l[j][i] += l[j - 1][i] + d[j][i] - c[j - 1];
    }

    For(i, 1, n){
        For(j, 1, i) if(l[j][i] > f[1][i]){
            f[1][i] = l[j][i];
        }
    }

    For(run, 2, num){
        For(i, 1, n){
            f[run][i] = f[run][i - 1];
            For(j, 1, i) if(f[run][i] < f[run - 1][j - 1] + l[j][i]){
                f[run][i] = f[run - 1][j - 1] + l[j][i];
            }
        }
    }

    cout << f[num][n] << endl;
}