思路：树链剖分+线段树+差分

按照题解的思路打的，找不出错误在哪里 qwq

#include<iostream>
#include<vector>
#include<algorithm>
using namespace std;
#define MAXN 50005
#define LL long long
#define MOD 201314

vector <int> E[MAXN];
struct Node{
    int l, r;
    int sum, lzy;
}tr[MAXN << 3];
struct Q{
    int r, z, op, ans;
    int ID;
}que[MAXN * 2];
int rec[MAXN];

int fa[MAXN], dep[MAXN], siz[MAXN], w[MAXN];
int son[MAXN], top[MAXN], id[MAXN], nw[MAXN];
int n, m, cnt = 0;

void dfs1(int fath, int u)
{
    fa[u] = fath, dep[u] = dep[ fa[u] ] + 1, siz[u] = 1;
    for(int v : E[u])
    {
        if(v == fa[u])
            continue;

        dfs1(u, v);
        siz[u] += siz[v];
        if(siz[v] > siz[ son[u] ])
            son[u] = v;
    }
}

void dfs2(int tp, int u)
{
    top[u] = tp, id[u] = ++ cnt, nw[ cnt ] = w[u];
    if(son[u] == 0)
        return ;
    dfs2(tp, son[u]);

    for(int v : E[u])
    {
        if(v == fa[u] || v == son[u])
            continue;

        dfs2(v, v);
    }
}

void pushup(int op)
{
    tr[op].sum = tr[op*2].sum + tr[op*2+1].sum;
}

void pushdown(int op);

void Build(int op, int L, int R)
{
    int mid = (L + R) >> 1;
    tr[op].l = L, tr[op].r = R;
    tr[op].sum = 0, tr[op].lzy = 0;

    if(L == R)
        return ;

    Build(op*2, L, mid);
    Build(op*2+1, mid+1, R);
    pushup(op);
}

int query(int op, int L, int R)
{
    int mid = (tr[op].l + tr[op].r) >> 1;
    if(tr[op].l == L && tr[op].r == R)
        return tr[op].sum % MOD;

    pushdown(op);
    if(R <= mid)
        return query(op*2, L, R);
    else if(L > mid)
        return query(op*2+1, L, R);
    else
        return (query(op*2, L, mid) + query(op*2+1, mid+1, R)) % MOD;
}

void add(int op, int L, int R, int val)
{
    int mid = (tr[op].l + tr[op].r) >> 1;
    if(tr[op].l == L && tr[op].r == R)
    {
        tr[op].sum = (tr[op].sum + (R-L+1) * val) % MOD;
        tr[op].lzy = (tr[op].lzy + val) % MOD;
        return ;
    }

    pushdown(op);
    if(R <= mid)
        add(op*2, L, R, val);
    else if(L > mid)
        add(op*2+1, L, R, val);
    else
    {
        add(op*2, L, mid, val);
        add(op*2+1, mid+1, R, val);
    }
    pushup(op);
}

void pushdown(int op)
{
    if(tr[op].lzy == 0)
        return ;

    add(op*2, tr[op*2].l, tr[op*2].r, tr[op].lzy);
    add(op*2+1, tr[op*2+1].l, tr[op*2+1].r, tr[op].lzy);
    tr[op].lzy = 0;
    return ;
}

void add_path(int u, int v, int val)
{
    while(top[u] != top[v])
    {
        if(dep[ top[u] ] < dep[ top[v] ])
            swap(u, v);

        add(1, id[ top[u] ], id[u], val);
        u = fa[top[u]];
    }

    if(dep[u] < dep[v])
        swap(u, v);
    add(1, id[v], id[u], val);
}

int query_path(int u, int v)
{
    int ans = 0;
    while(top[u] != top[v])
    {
        if(dep[ top[u] ] < dep[ top[v] ])
            swap(u, v);

        ans = ( ans + query(1, id[ top[u] ], id[u]) ) % MOD;
        u = fa[top[u]];
    }
    
    if(dep[u] < dep[v])
        swap(u, v);
    return ( ans + query(1, id[v], id[u]) ) % MOD;
}

bool cmp(Q a, Q b)
{
	return a.r < b.r;
}

int main()
{
    cin >> n >> m;
    for(int i = 2; i <= n; i ++)
    {
        int f;
        cin >> f; f ++;
        E[i].push_back(f);
        E[f].push_back(i);
    }

    for(int i = 1; i <= m; i ++)
    {
        int L, R, z;
        cin >> L >> R >> z;
        L ++, R ++;
        que[i].r = L-1, que[i].z = z,
		que[i].op = 1, que[i].ID = i;
		
        que[i+m].r = R, que[i+m].z = z,
		que[i+m].op = 2, que[i+m].ID = i;
    }
    
    dfs1(0, 1);
    dfs2(1, 1);
    Build(1, 1, n);
    
    sort(que+1, que+1+m+m, cmp);
    int ind = 1;
    for(int i = 1; i <= n && ind <= 2*m; i ++)
    {
    	add_path(1, i, 1);
    	while(que[ind].r == i)
    	{
    		que[ind].ans = query_path(1, que[ind].z);
    		ind ++;
    	}
	}
	
	for(int i = 1; i <= 2*m; i ++)
	{
		if(que[i].op == 1)
			rec[ que[i].ID ] -= que[i].ans;
		else
			rec[ que[i].ID ] += que[i].ans;
	}
	
	for(int i = 1; i <= m; i ++)
		cout << (rec[i] + MOD) % MOD << '\n';
    return 0;
}