这个代码虽复杂度不对，但是题目所给附件的样例都过了，为什么会是全WA？

#include <bits/stdc++.h>
using namespace std;
#define int long long
const int N = 2e5 + 100;
int n, c, q, oqt, x, ans, t;
int a[N], b[N];
struct segyid {
	int l, r, maxn, sum;
} tree[N * 4];
void make_tree(int p, int l, int r) {
	tree[p].l = l, tree[p].r = r;
	if(l == r) {
		tree[p].sum = b[l];
		tree[p].maxn = b[l];
		return;
	}
	int mid = l + r >> 1;
	make_tree(p << 1, l, mid);
	make_tree(p << 1 | 1, mid + 1, r);
	tree[p].maxn = max(tree[p << 1].maxn, tree[p << 1 | 1].maxn);
}
signed main()
{
// 	freopen("a.in", "r", stdin);
// 	freopen("a.out", "w", stdout);
	std::ios::sync_with_stdio(false);
	std::cin.tie(0);
	cin >> c >> q;
	while(q --) {
		cin >> oqt;
		if(oqt == 1) {
			cin >> x;
			a[++ t] = a[t - 1] + x;
			b[t] = x;
		} else if(oqt == 2) {
			cin >> x;
			ans += x;
		} else if(oqt == 3) {
			cin >> x;
			x += ans;
//			if(a[lower_bound(a + 1, a + 1 + t, ans) - a] - ans >= x) {
//				cout << b[lower_bound(a + 1, a + 1 + t, ans) - a] - (a[lower_bound(a + 1, a + 1 + t, ans) - a] - ans - x) << "\n";
//			}
//			else {
//				x -= a[lower_bound(a + 1, a + 1 + t, ans) - a] - ans;
//			}
			cout << b[lower_bound(a + 1, a + 1 + t, x) - a] - (a[lower_bound(a + 1, a + 1 + t, x) - a] - x) << "\n";
		} else {
			make_tree(1, upper_bound(a + 1, a + 1 + t, ans) - a, t);
			cout << tree[1].maxn << "\n";
			
		}
	} 
	return 0;
}