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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 <iostream>
#include <cstdio>
#include <algorithm>
#include <vector>
#include <cmath>
#define ii pair<int, int>
#define X first
#define Y second
const int N = 100005;
using namespace std;
int lang[N], ans[N], cnt[N], dis[N], fin[N], ver[N];
vector<int> a[N];
int n, m, k, timer, now, len;

struct query {
    int l, r, id;
    query(int _l = 0, int _r = 0, int _id = 0)
        {l = _l; r = _r; id = _id;}
    bool operator < (const query &b) const {
        return l / len < b.l / len || (l / len == b.l / len && r < b.r);
    }
} Q[N];

void DFS(int u) {
    dis[u] = ++timer;
    ver[timer] = u;
    for(int i = 0; i < a[u].size(); i++) 
        DFS(a[u][i]);
    fin[u] = timer;
}

void Inc(int i) {
    cnt[lang[ver[i]]]++;
    if (cnt[lang[ver[i]]] == 1) now++; else
    if (cnt[lang[ver[i]]] == k + 1) now--;
}

void Dec(int i) {
    cnt[lang[ver[i]]]--;
    if (cnt[lang[ver[i]]] == 0) now--; else
    if (cnt[lang[ver[i]]] == k) now++;
}
int main() {
    ios :: sync_with_stdio(0); cin.tie(0);
    cin >> n >> m >> k;
    int p, q;
    for(int i = 2; i <= n; i++) {
        cin >> p;
        a[p].push_back(i);
    }
    DFS(1);
    for(int i = 1; i <= n; i++) cin >> lang[i];
    cin >> q;
    for(int i = 0; i < q; i++) {
        cin >> p;
        Q[i] = query(dis[p], fin[p], i);
    }
    len = sqrt(n);
    sort(Q, Q + q);
    int l = 0, r = 0;
    for(int i = 0; i < q; i++) {
        while (Q[i].l < l) Inc(--l);
        while (Q[i].r > r) Inc(++r);
        while (Q[i].l > l) Dec(l++);
        while (Q[i].r < r) Dec(r--);
        ans[Q[i].id] = now;
    }
    for(int i = 0; i < q; i++)
        cout << ans[i] << '\n';
    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);
const int MN = 100111;

int n, m, k, color[MN], getIn[MN], getOut[MN], num, st[MN], top, res[MN], id[MN], next[MN], nextk[MN];
vector<int> ls[MN], ke[MN];
vector<int> query[MN];

int bit[MN];

#define _(x) ((x) & (-(x)))

int get(int u) {
    int res = 0;
    while (u > 0) {
        res += bit[u];
        u -= _(u);
    }
    return res;
}

void update(int u, int k) {
    while (u <= n) {
        bit[u] += k;
        u += _(u);
    }
}

void dfs(int u) {
    getIn[u] = ++num;
    st[++top] = u;
    id[u] = ls[color[u]].size();
    ls[color[u]].push_back(getIn[u]);

    REP(i,ke[u].size()) {
        int v = ke[u][i];
        dfs(v);
    }
    getOut[u] = num;
}

void solve() {
    dfs(1);
    // PR(st, top);

    FORD(i,n,1) {
        int u = st[i];
        int id_next = id[u] + 1;
        next[u] = (id_next >= ls[color[u]].size()) ? (n+1) : ls[color[u]][id_next];

        int id_nextk = id[u] + k;
        nextk[u] = (id_nextk >= ls[color[u]].size()) ? (n+1) : ls[color[u]][id_nextk];

        update(next[u], 1);
        res[u] = (getOut[u] - getIn[u] + 1) - get(getOut[u]);
    }
    // PR(res, n);
    memset(bit, 0, sizeof bit);

    FORD(i,n,1) {
        int u = st[i];

        update(nextk[u], 1);
        int v = next[u];
        if (v <= n) {
            v = st[v];
            update(nextk[v], -1);
        }

        res[u] = res[u] - get(getOut[u]);
    }
    // PR(res, n);
}

int main() {
    scanf("%d%d%d", &n, &m, &k);
    FOR(v,2,n) {
        int u; scanf("%d", &u);
        ke[u].push_back(v);
    }
    FOR(i,1,n) scanf("%d", &color[i]);
    solve();
    int q; scanf("%d", &q);
    while (q--) {
        int u; scanf("%d", &u);
        printf("%d\n", res[u]);
    }
    return 0;
}

Code mẫu của skyvn97

#include<cstdio>
#include<map>
#include<vector>
#define MAX   100100
#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)
#define fi   first
#define se   second
using namespace std;
vector<int> g[MAX];
int ans[MAX],sub[MAX],nChild[MAX];
map<int,int> *cnt[MAX];
int n,m,lim;
void loadtree(void) {
    scanf("%d%d%d",&n,&m,&lim);
    FOR(i,2,n) {
        int p;
        scanf("%d",&p);
        g[p].push_back(i);
    }
    FOR(i,1,n) scanf("%d",&sub[i]);
}
void dfs(int u) {
    int best=-1;
    nChild[u]=1;
    REP(i,g[u].size()) {
        int v=g[u][i];
        dfs(v);
        nChild[u]+=nChild[v];
        if (best<0 || cnt[best]->size()<cnt[v]->size()) best=v;
    }
    if (best<0) {
        cnt[u]=new map<int,int>();
        (*cnt[u])[sub[u]]++;
        ans[u]=1;
    } else {
        ans[u]=ans[best];
        cnt[u]=cnt[best];
        REP(i,g[u].size()) if (g[u][i]!=best) {
            int v=g[u][i];
            map<int,int> &cur=*cnt[v];
            for (map<int,int>::iterator it=cur.begin();it!=cur.end();it++) {
                int &val=(*cnt[u])[it->fi];
                int bef=1<=val && val<=lim;
                val+=it->se;
                int aft=1<=val && val<=lim;
                ans[u]+=aft-bef;
            }
        }
        int &tmp=(*cnt[u])[sub[u]];
        int before=1<=tmp && tmp<=lim;
        tmp++;
        int after=1<=tmp && tmp<=lim;
        ans[u]+=after-before;
    }
}
void process(void) {
    dfs(1);
    int q;
    scanf("%d",&q);
    REP(love,q) {
        int u;
        scanf("%d",&u);
        printf("%d\n",ans[u]);
    }
}
int main(void) {
    loadtree();
    process();
    return 0;
}