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

const maxn=1010;
var n,re,x,y,z:longint;
    a:array[1..maxn,0..maxn] of longint;
    d:array[1..maxn] of longint;

procedure rf;
var i,j,z,t:longint;
begin
     t:=0; z:=1;
     readln(n);
     for i:=1 to n do
         for j:=1 to n do
         begin
              read(a[i,j]);
              if (i>j) and (a[i,j]+a[j,i]<>1) then z:=z div t;
         end;
     for i:=1 to n do a[i,0]:=1;
end;

procedure pr;
var i,j,t:longint;
begin
     re:=0;
     d[1]:=1;
     for i:=2 to n do
     begin
          for j:=1 to i do
              if a[i,d[j]]=1 then break;
          for t:=j+1 to i-1 do
              if a[i,d[t]]=0 then
              begin
                   re:=1;
                   x:=i; y:=d[j]; z:=d[t];
                   exit;
              end;
          for t:=i downto j+1 do d[t]:=d[t-1];
          d[j]:=i;
     end;
end;

procedure wf;
begin
     if re=0 then writeln('-1 -1 -1')
     else writeln(x,' ',y,' ',z);
end;

begin
     rf;
     pr;
     wf;
end.

Code mẫu của ladpro98

program nktrio;
uses    math;
const   maxN=1001;
        fi='';
var     a:array[1..maxN,1..maxN] of longint;
        c:array[1..maxN] of longint;
        inStack:array[1..maxN] of boolean;
        n,i,count,res:longint;

procedure input;
var     inp:text;
        i,j:longint;
begin
        assign(inp,fi);
        reset(inp);
        readln(inp,n);
        for i:=1 to n do
        for j:=1 to n do
        read(inp,a[i,j]);
        close(inp);
end;

procedure output;
var     i,j:longint;
begin
        for i:=1 to n do
        for j:=1 to n do
        if (a[res,i]=1) and (a[i,j]=1) and (a[j,res]=1) then
        begin
                write(res,' ',i,' ',j);
                exit;
        end;
end;

procedure dfs(i:longint);
var     j:longint;
begin
        c[i]:=count;
        for j:=1 to n do
        if a[i,j]=1 then
        begin
                if inStack[j] then
                begin
                        res:=j;
                        output;
                        halt;
                end;
                if c[j]=0 then
                begin
                        inStack[j]:=true;
                        dfs(j);
                        inStack[j]:=false;
                end;
        end;
end;

begin
        input;
        count:=0;
        for i:=1 to n do
        if c[i]=0 then
        begin
                inc(count);
                inStack[i]:=true;
                dfs(i);
                instack[i]:=false;
        end;
        write(-1,' ',-1,' ',-1);

end.

Code mẫu của RR

//Written by RR
{$R+,Q+}
uses math;
const
  FINP          =       '';
  FOUT          =       '';
  MAXN          =       1111;
var
  f1,f2         :       text;
  father        :       array[1..MAXN] of longint;
  c             :       array[1..MAXN,1..MAXN] of longint;
  n             :       longint;

procedure openF;
    begin
      assign(f1,FINP); reset(f1);
      assign(f2,FOUT); rewrite(f2);
    end;
procedure closeF;
    begin
      close(f1);
      close(f2);
    end;
procedure inp;
    var
      i,j:longint;
    begin
      readln(f1,n);
      for i:=1 to n do
        begin
          for j:=1 to n do
            read(f1,c[i,j]);
          readln(f1);
        end;
    end;
procedure dfs(u:longint);
    var
      v:longint;
    begin
      for v:=1 to n do
      if c[u,v]=1 then
        if father[v]=0 then
          begin
            father[v]:=u;
            dfs(v);
          end
        else if (father[u]>0) and (c[v,father[u]]=1) then
          begin
            writeln(f2,u,' ',v,' ',father[u]);
            closeF;
            halt;
          end;
    end;

var
  i:longint;

begin
  openF;
  inp;
  for i:=1 to n do
    if father[i]=0 then
      begin
        father[i]:=-1;
        dfs(i);
      end;
  writeln(f2,'-1 -1 -1');
  closeF;
end.

Code mẫu của hieult

#include <iostream>
#include <cstdio>
#include <map>
#include <set>
#include <vector>
#include <cmath>
#include <algorithm>
#include <stack>
#include <queue>
#include <cstring>
#include <string>
using namespace std;
#define REP(i,a,b) for(int i=a;i<=b;++i)
#define DOWN(i,a,b) for(int i=a;i>=b;--i)
#define EPS 1e-9

int s[2005][2005];
struct Point{
    int deg;
    int pos;
    bool operator<(const Point& that)const{
        return deg<that.deg;
    }
};

Point d[5005];
int main()

{
//  freopen("NKTRIO.IN", "rt", stdin);
    //freopen("NKTRIO.out","wt",stdout);
    int n;
    scanf("%d",&n);
    REP(i,0,n){
            d[i].pos=i;
            d[i].deg=0;
    }
    REP(i,0,n-1){
        REP(j,0,n-1){
            scanf("%d",&s[i][j]);
            if(s[i][j]){
                d[i].deg++;
            }
        }
    }
//  REP(i,0,n-1)
//  {
//      REP(j,0,n-1)
//      cout<<s[i][j]<<" ";
//      cout<<endl;
//  }
    sort(d,d+n);
    REP(i,0,n-2){
        if(d[i].deg==d[i+1].deg){
            int a=d[i].pos;
            int b=d[i+1].pos;
            DOWN(j,n-1,0){
                if(s[b][a]==1)
                {
                    if(s[a][j]==1 && s[j][b]==1)
                    {
                        cout<<a+1<<" "<<j+1<<" "<<b+1;
                        return 0;
                    }
                }
                else
                {
                    if(s[b][j]==1 && s[j][a]==1)
                    {
                        cout<<b+1<<" "<<j+1<<" "<<a+1;
                        return 0;
                    }
                }
            }
        }
    }
//  //Cach 2.
//  cout<<"\n Duyet theo cach trau"<<endl;
//  REP(i,0,n-1)
//  REP(j,0,n-1)
//  REP(t,0,n-1){
//      if(s[i][j]=='1' && s[j][t]=='1' && s[t][i]=='1'){
//          cout<<i+1<<" "<<j+1<<" "<<t+1<<endl;
//      }
//  }

    cout<<"-1 -1 -1";

    return 0;
}

Code mẫu của ll931110

program NKTRIO;
const
  input  = '';
  output = '';
  maxn = 1000;
var
  a: array[1..maxn,1..maxn] of integer;
  d: array[1..maxn] of integer;
  n: integer;

procedure init;
var
  f: text;
  i,j: integer;
begin
  assign(f, input);
    reset(f);

  readln(f, n);
  for i := 1 to n do
    for j := 1 to n do read(f, a[i,j]);

  close(f);
end;

procedure solve;
var
  f: text;
  i,j,k: integer;
begin
  assign(f, output);
    rewrite(f);

  fillchar(d, sizeof(d), 0);
  d[1] := 1;
  for i := 2 to n do
    begin
      j := 1;
      while (j < i) and (a[i,d[j]] = 0) do inc(j);
      if j = i then d[i] := i else
        begin
          for k := j + 1 to i - 1 do
            if a[i,d[k]] = 0 then
              begin
                writeln(f, i, ' ', d[j], ' ', d[k]);
                close(f);
                exit;
              end;

          for k := i downto j + 1 do d[k] := d[k - 1];
          d[j] := i;
        end;
    end;

  writeln(f, -1, ' ', -1, ' ', -1);
  close(f);
end;

begin
  init;
  solve;
end.

Code mẫu của skyvn97

#include<cassert>
#include<cstdio>
#include<cstring>
#include<stack>
#include<vector>
#define MAX   1010
#define FOR(i,a,b) for (int i=(a),_b=(b);i<=_b;i=i+1)
#define REP(i,n) for (int i=0,_n=(n);i<_n;i=i+1)
using namespace std;
int win[MAX][MAX];
int low[MAX],num[MAX],compID[MAX],compSZ[MAX],vstID[MAX];
int n,cnt,nComp;
stack<int> st;
void loadgraph(void) {
    scanf("%d",&n);
    FOR(i,1,n) FOR(j,1,n) scanf("%d",&win[i][j]);
}
void dfs(int u) {
    low[u]=num[u]=++cnt;
    st.push(u);
    FOR(v,1,n) if (win[u][v] && compID[v]==0) {
        if (num[v]==0) {
            dfs(v);
            low[u]=min(low[u],low[v]);
        } else low[u]=min(low[u],num[v]);
    }
    if (low[u]==num[u]) {
        nComp++;
        int v;
        do {
            v=st.top();st.pop();
            compID[v]=nComp;
            compSZ[nComp]++;
        } while (v!=u);
    }
}
int getNext(int u) {
    FOR(v,1,n) if (win[u][v] && compID[u]==compID[v]) return (v);
}
vector<int> circle(int u) {
    memset(vstID,-1,sizeof vstID);
    vector<int> path;
    while (true) {
        if (vstID[u]>=0) return (vector<int>(path.begin()+vstID[u],path.end()));
        vstID[u]=path.size();
        path.push_back(u);
        u=getNext(u);
    }
}
void process(void) {
    FOR(i,1,n) if (num[i]==0) dfs(i);
    FOR(i,1,nComp) if (compSZ[i]>=3)
        FOR(s,1,n) if (compID[s]==i) {
            vector<int> cir=circle(s);
            FOR(j,2,(int)cir.size()-1) if (win[cir[j]][cir[0]]) {
                int u=cir[0];
                int v=cir[j-1];
                int w=cir[j];
                assert(win[u][v] && win[v][w] && win[w][u]);
                printf("%d %d %d\n",u,v,w);
                return;
            }
        }
    printf("-1 -1 -1\n");
}
int main(void) {
    loadgraph();
    process();
    return 0;
}

Code mẫu của khuc_tuan

// {$APPTYPE CONSOLE}
{$MODE DELPHI}

var
    n, i, j : integer;
    a : array[1..1000,1..1000] of integer;
    visiting, vs : array[1..1000] of boolean;
    b : array[1..1000] of integer;
    s : array[1..1000] of integer;
    ns : integer;

procedure getcycle(st, en : integer);
var
    i : integer;
begin
    i := en;
    while i <> st do
    begin
        inc(ns);
        s[ns] := i;
        i := b[i];
    end;
    inc(ns);
    s[ns] := i;
    for i:= 1 to ns do
    begin
        if a[s[i], s[i+2]]=1 then
        begin
            writeln(s[i], #32, s[i+2], #32, s[i+1]);
            halt;
        end;
        s[i+1] := s[i];
    end;
end;

procedure dfs(i : integer);
var
    j : integer;
begin
    vs[i] := true;
    visiting[i] := true;
    for j:=1 to n do
        if (a[i,j]=1) then
        begin
            if not vs[j] then
            begin
                b[j] := i;
                dfs(j);
            end
            else
            begin
                if visiting[j] then getcycle(j,i);
            end;
        end;
    visiting[i] := false;
end;

begin
    read(n);
    for i:=1 to n do
        for j:=1 to n do
            read(a[i,j]);
    for i:=1 to n do
        if not vs[i] then
            dfs(i);
    writeln('-1 -1 -1');
end.