这个代码到底哪里有编译错误的问题呀，都快把提交记录弄成这样了，大佬快来救救我呀！

#include <bits/stdc++.h>
using namespace std;

int cnt;
struct node{
	int left, right, size, value, num;
	node(int l, int r, int s, int v) {
		left = l, right = r, size = s, value = v, num = 1; 
	}
	node() {} 
}t[100010];

void update(int root) {
	t[root].size = t[t[root].left].size + t[t[root].right].size + t[root].num;
}

int rank(int x, int root) {
	if(root) {
		if(x < t[root].value) return rank(x, t[root].left);
		if(x > t[root].value) return rank(x, t[root].right) + t[t[root].left].size + t[root].num;
		return t[t[root].left].size + t[root].num;
	}
	return 1;
}

int kth(int x, int root) {
	if(x <= t[t[root].left].size) return kth(x, t[root].left);
	if(x <= t[t[root].left].size + t[root].num) return t[root].value;
	return kth(x - t[t[root].left].size - t[root].num, t[root].right); 
}

void insert(int x, int root) {
	if(x < t[root].value)
		if(!t[root].left) t[t[root].left = ++cnt] = node{0, 0, 1, x};
		else insert(x, t[root].left);
	else if(x > t[root].value)
		if(!t[root].right) t[t[root].right = ++cnt] = node{0, 0, 1, x};
		else insert(x, t[root].right);
	else t[root].num++;
	update(root); 
}

int main() {
	int n = 0, root = 0, opt = 0, x = 0;
	cin >> n;
	t[root = ++cnt] = node(0, 0, 1, 2147483647);
	while(n--) {
		cin >> opt >> x;
		if(opt == 1) cout << rank(x, root) << endl;
		else if(opt == 2) cout << kth(x, root) << endl;
		else if(opt == 3) cout << kth(rank(x, root) - 1, root) << endl;
		else if(opt == 4) cout << kth(rank(x + 1, root), root) << endl;
		else if(opt == 5) insert(x, root);
	}
    return 0;
}