WA+RE 0分求助

#include <bits/stdc++.h>
using namespace std;
struct Query {
    int op, l, r;
};
vector<Query> qs;
const int N = 1e5 + 10, M = 4 * N;
int w[N];
int sum[M], tag[M], len[M];
int n;
int pos;
void pushup(int u) {
    sum[u] = sum[u * 2] + sum[u * 2 + 1];
}
void update(int u, int v) {
    tag[u] = v;
    if (!v) sum[u] = 0;
    else sum[u] = len[u];
}
void pushdown(int u) {
    if (tag[u] != -1) {
        update(u * 2, tag[u]), update(u * 2 + 1, tag[u]);
        tag[u] = -1;
    }
}
void build(int u, int l, int r, int x) {
    len[u] = r - l + 1;
    tag[u] = -1;
    if (l == r) {
        sum[u] = (w[l] >= x ? 1 : 0);
        return;
    }
    int mid = (l + r) >> 1;
    build(u * 2, l, mid, x), build(u * 2 + 1, mid + 1, r, x);
}
void modify(int u, int l, int r, int L, int R, int v) {
    if (l >= L and r <= R) {
        update(u, v);
        return; 
    }
    pushdown(u);
    int mid = (l + r) >> 1;
    if (L <= mid) modify(u * 2, l, mid, L, R, v);
    if (R > mid) modify(u * 2 + 1, mid + 1, r, L, R, v);
    pushup(u);
}
int query(int u, int l, int r, int L, int R) {
    if (l >= L and r <= R) return sum[u];
    pushdown(u);
    int mid = (l + r) >> 1;
    int ans = 0;
    if (L <= mid) ans = query(u * 2, l, mid, L, R);
    if (R > mid) ans += query(u * 2 + 1, mid + 1, r, L, R);
    return ans;
}
bool check(int mid) {
    build(1, 1, n, mid);
    for (auto q : qs) {
        int s = query(1, 1, n, q.l, q.r);
        if (!q.op) {
            modify(1, 1, n, q.l, q.r - s, 0);
            modify(1, 1, n, q.r - s + 1, q.r, 1);
        } else {
            modify(1, 1, n, q.l, q.l + s - 1, 1);
            modify(1, 1, n, q.l + s, q.r, 0);
        }
    }
    return query(1, 1, n, pos, pos) == 1;
}
int main() {
    ios::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    int m;
    cin >> n >> m;
    for (int i = 1; i <= n; i++) cin >> w[i];
    for (int i = 1; i <= m; i++) {
        int op, l, r;
        cin >> op >> l >> r;
        qs.push_back({op, l, r});
    }
    cin >> pos;
    int l = 1, r = n, mid, ans;
    while (l <= r) {
        int mid = (l + r) >> 1;
        if (check(mid)) {
            l = mid + 1;
            ans = mid;
        } else r = mid - 1;
    }
    cout << ans << '\n';
    return 0;
}