这道题要注意空间不能开太小，还有我第一次是build函数忘写return了，我很奇怪，结构体数组开小后，有一个报错和tle，不知道tle是怎么来的
#include<iostream>
#include<set>
#include<map>
#include<algorithm>
#include<vector>
#include<cmath>
#include<climits>
#include<cstring>
#define int long long
const int N = 1e6+5;
using namespace std;
char* p1, * p2, buf[100000];
#define nc() (p1==p2 && (p2=(p1=buf)+fread(buf,1,100000,stdin),p1==p2)?EOF:*p1++)
int read()
{int x = 0, f = 1;char ch = nc();while (ch < 48 || ch>57){if (ch == '-')f = -1;ch = nc();}while (ch >= 48 && ch <= 57)x = x * 10 + ch - 48, ch = nc();return x * f;
}
int a[N], id=0,root[N];
struct tree {int left;int right;int val;
}tr[N*40];
void build(int& x, int l, int r) {x = ++id;if (l == r) { tr[x].val = a[l]; return; }int mid = (l + r) >> 1;build(tr[x].left, l, mid);build(tr[x].right, mid + 1, r);
}
void change(int x, int& y, int l, int r,int p ,int k) {y = ++id;tr[y] = tr[x];if (l == r) { tr[y].val = k; return; }int mid = (l + r) >> 1;if (p <= mid)change(tr[x].left, tr[y].left, l, mid, p, k);else change(tr[x].right, tr[y].right, mid+1, r, p, k);
}
int query(int x,int l, int r, int p) {if (l == r) { return tr[x].val; }int mid = (l + r) >> 1;if (p <= mid)return query(tr[x].left, l, mid, p);else return query(tr[x].right, mid+1, r, p);
}
signed main() {ios::sync_with_stdio(false);cin.tie(0);cout.tie(0);int n, m;cin >> n >> m;for (int i = 1; i <= n; i++)cin >> a[i];build(root[0], 1, n);for (int i = 1; i <= m; i++) {int ver, op;cin >> ver >> op;if (op == 1) {int p, k;cin >> p >> k;change(root[ver], root[i], 1, n, p, k);}else {int p;cin >> p;cout << query(root[ver], 1, n, p) << endl;root[i] = root[ver];}}return 0;
}
