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>
#include <vector>
using namespace std;

int n, color[100100], ans;
vector <int> a[100100];

void visit(int x, int par)
{
    for (int i = 0; i < int(a[x].size()); i++)
    {
        int y = a[x][i];
        if (y == par) continue;
        if (color[y] < 0) color[y] = 1 ^ color[x], visit(y, x);
        else
            if (color[y] == color[x]) ans = 0;
    }
}

int main()
{
    int test, m, x, y;
    cin >> test;
    while (test--)
    {
        cin >> n >> m;
        for (int i = 1; i <= n; i++) color[i] = -1, a[i].clear();

        while (m--) 
        {
            scanf("%d%d", &x, &y);
            a[x].push_back(y);
            a[y].push_back(x);
        }

        ans = 1;
        for (int i = 1; i <= n; i++)
            if (color[i] < 0) color[i] = 0, visit(i, 0);
        cout << ans << endl;
    }
}

Code mẫu của ladpro98

program vmrelate;
uses    math;
const   fi='';
        maxn=200009;
var     adj,link,head,q,d:array[1..maxn] of longint;
        check:array[1..maxn] of boolean;
        n,m,t,tt,i,mm,x,y:longint;
        ok:boolean;
        inp:text;

function bfs(s:longint):boolean;
var     l,r,u,i:longint;
begin
        l:=1;r:=1;
        q[1]:=s;
        d[s]:=0;
        check[s]:=true;
        while l<=r do
        begin
                u:=q[l];inc(l);
                i:=head[u];
                while i>0 do
                begin
                        if not check[adj[i]] then
                        begin
                                check[adj[i]]:=true;
                                inc(r);
                                q[r]:=adj[i];
                                d[adj[i]]:=d[u]+1;
                        end
                        else if d[adj[i]] = d[u] then exit(true);
                        i:=link[i];
                end;
        end;
        exit(false);
end;

begin
        assign(inp,fi);reset(inp);
        readln(inp,t);readln(inp);
        for tt:=1 to t do
        begin
                readln(inp,n,mm);
                m:=0;
                for i:=1 to n do head[i]:=0;
                for i:=1 to mm do
                begin
                        readln(inp,x,y);
                        inc(m);adj[m]:=y;link[m]:=head[x];head[x]:=m;
                        inc(m);adj[m]:=x;link[m]:=head[y];head[y]:=m;
                end;
                for i:=1 to n do check[i]:=false;
                ok:=false;
                for i:=1 to n do if not check[i] then
                begin
                        if bfs(i) then
                        begin
                                ok:=true;
                                break;
                        end;
                end;
                if ok then writeln(0)
                else    writeln(1);
                readln(inp);
        end;
end.

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
using namespace std;

const int MN = 100111;

int n, m, color[MN];
vector<int> ke[MN];
queue<int> q;

bool bfs(int start) {
    while (!q.empty()) q.pop();
    q.push(start);
    color[start] = 0;
    while (!q.empty()) {
        int u = q.front(); q.pop();
        REP(i,ke[u].size()) {
            int v = ke[u][i];
            if (color[v] >= 0) {
                if (color[u] == color[v]) return false;
            }
            else {
                color[v] = 1 - color[u];
                q.push(v);
            }
        }
    }
    return true;
}

int main() {
    int ntest; scanf("%d", &ntest);
    while (ntest--) {
        scanf("%d%d", &n, &m);
        FOR(i,1,n) ke[i].clear();
        memset(color, -1, sizeof color);

        int u, v;
        while (m--) {
            scanf("%d%d", &u, &v);
            ke[u].PB(v);
            ke[v].PB(u);
        }
        bool ok = true;
        FOR(i,1,n) if (color[i] < 0) {
            if (!bfs(i)) {
                ok = false;
                puts("0");
                break;
            }
        }
        if (ok) puts("1");
    }
    return 0;
}

Code mẫu của hieult

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

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(typeof(n) i = 0; i < (n); ++i)
#define Repd(i,n) for(typeof(n) i = (n)-1; i >= 0; --i)
#define For(i,a,b) for(typeof(b) i = (a); i <= (b); ++i)
#define Ford(i,a,b) for(typeof(a) 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))
#define nl puts("")
#define sp printf(" ")
#define ok puts("ok")

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> void db(T a, int p = -1) { if (p >= 0) cout << fixed << setprecision(p); cout << a << " "; }
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> struct Triple { T x, y, z; Triple() {} Triple(T _x, T _y, T _z) : x(_x), y(_y), z(_z) {} };
template<class T> Triple<T> euclid(T a, T b) { if (b == 0) return Triple<T>(1, 0, a); Triple<T> r = euclid(b, a % b); return Triple<T>(r.y, r.x - a / b * r.y, r.z); }
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 = 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;
}

const double PI = 2 * acos(0);
const string months[] = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
const int days[] = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
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 double eps = 1e-9;

const int MAXN = 500005;

int n, m, E, cnt, adj[MAXN], next[MAXN], last[MAXN], col[MAXN];
bool canColor;

void add(int u, int v) {
    adj[E] = v; next[E] = last[u]; last[u] = E++;
}

void color(int u) {
    for (int e = last[u]; e != -1; e = next[e]) {
        int v = adj[e];
        if (col[v] == 0) {
            col[v] = 3 - col[u]; ++cnt;
            color(v);
        }
        else if (col[v] == col[u]) canColor = false;
    }
}


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

    int ntest;
    gi(ntest);

    For(test, 1, ntest) {
        gi(n); gi(m);

        E = 0;
        Rep(u, n) last[u] = -1;

        int u, v;
        Rep(i, m) {
            gi(u); gi(v); --u; --v;
            add(u, v); add(v, u);
        }

        int res = 1;
        Rep(u, n) col[u] = 0;

        Rep(u, n) if (col[u] == 0) {
            col[u] = 1;
            canColor = true;
            color(u);
            if (!canColor) res = 0;
        }

        printf("%d\n", res);
    }

    return 0;
}