大了MLE，小了CE

请问我该怎么调整数组大小。还是说代码本身无法通过

还有就是一般数组开最大能开多大比如char int等等。望详细讲解

#include<bits/stdc++.h>
#define int long long
using namespace std;
struct node{
    int v, next;
}edge[200100];
int fa[200100], head[200100], w[200100], w_new[200100], cnt, tot = 1, N, M, R, P, tree[400100], deep[200100], size[400100], son[200100], top[200100], id[200100], tag[400100];
void add(int u, int v) {edge[tot].v = v;edge[tot].next = head[u];head[u] = tot++;}
void build(int l, int r, int index) {
    if(l == r) {
        tree[index] = w_new[l] % P;
        return;
    }
    int mid = l+r >> 1;
    build(l, mid, index*2);
    build(mid+1, r, index*2+1);
    tree[index] = tree[index*2] + tree[index*2+1];
    tree[index] %= P;
}
int push_down(int l, int r, int index) {
    tag[index*2] += tag[index],tag[index*2]%=P;
    tag[index*2+1] += tag[index],tag[index*2+1]%=P;
    tree[index] += (r-l+1) * tag[index],tree[index]%=P;
    tag[index]=0;
}
void update(int l, int r, int index, int left, int right, int x) {
    push_down(l, r, index);
    if(left <= l && r <= right) {
        tag[index]+=x;
        tag[index] %= P;
        return;
    }
    if(l > right || r < left) {
        return;
    }
    int mid = l+r>>1;
    update(l, mid, index*2, left, right, x);
    update(mid+1, r, index*2+1, left, right, x);
    push_down(l, mid, index*2);
    push_down(mid+1, r, index*2+1);
    tree[index] = tree[index*2] + tree[index*2+1];
    tree[index] %= P;
}
int query(int l, int r, int index, int left, int right) {
    push_down(l, r, index);
    if(left <= l && r <= right) {
        return tree[index] % P;
    }
    if(left > r || right < l) {
        return 0;
    }
    int mid = l + r >> 1;
    return (query(l, mid, index*2, left, right) + query(mid+1, r, index*2+1, left, right)) % P;
}
void input() {
    ios::sync_with_stdio(0); cin.tie(0);
    cin >> N >> M >> R >> P;
    for(int i = 1; i <= N; ++i) {cin >> w[i];}
    for(int i = 1, u, v; i < N; ++i) {cin >> u >> v;add(u, v); add(v, u);}
}
void dfs1(int index, int back, int depth) {
    fa[index] = back;
    size[index] = 1;
    deep[index] = depth;
    for(int i = head[index]; i; i = edge[i].next) {
        int to = edge[i].v;
        if(to == back) continue;
        dfs1(to, index, depth+1);
        if(son[index] == 0 || size[son[index]] < size[to])
            son[index] = to;
        size[index] += size[to];
    }
}
void dfs2(int index, int back, int topx) {
    id[index] = ++cnt;
    w_new[cnt] = w[index];
    top[index] = topx;
    if(!son[index]) return;
    dfs2(son[index], index, topx);
    for(int i = head[index]; i; i = edge[i].next) {
        int t = edge[i].v;
        if(t == back || t == son[index]) continue;
        dfs2(t, index, t);
    }
}
void update_tree(int index, int k) {
    update(1,N,1,id[index],id[index]+size[index]-1, k);
}
int q_tree(int index) {
    return query(1,N,1,id[index],id[index]+size[index]-1);
}
void update_range(int x, int y, int z) {
    while(top[x]!=top[y]) {
        if(deep[top[x]] < deep[top[y]]) swap(x, y);
        update(1,N,1,id[top[x]],id[x],z);
        x = fa[top[x]];
    }
    if(deep[x] > deep[y]) swap(x, y);
    update(1,N,1,id[x],id[y],z);
}
int q_range(int x, int y, int z) {
    int ans = 0;
    while(top[x]!=top[y]) {
        if(deep[top[x]] < deep[top[y]]) swap(x, y);
        ans += query(1,N,1,id[top[x]],id[x]);
        ans %= P;
        x = fa[top[x]];
    }
    if(deep[x] > deep[y]) swap(x, y);
    ans += query(1,N,1,id[x],id[y]);
    return ans%P;
}
signed main() {
    input();
    dfs1(R, 0, 1);
    dfs2(R, 0, R);
    build(1, N, 1);
    while(M--) {
        int k, x, y, z; cin >> k;
        switch(k) {
            case 1:cin >> x >> y >> z; update_range(x, y, z); break;
            case 2:cin >> x >> y; cout << q_range(x, y, z) << endl; break;
            case 3:cin >> x >> y; update_tree(x, y); break;
            case 4:cin >> x; cout << q_tree(x) << endl; break;
        }
    }
    return 0;
}

MLE https://www.luogu.com.cn/record/115545186 CE https://www.luogu.com.cn/record/115544068