#include <bits/stdc++.h>
#define pb push_back
#define fi first
#define se second
#define sz size
#define all(x) x.begin(), x.end()
#define pii pair<int, int>
#define int long long
#define mem(x, y) memset(x, y, sizeof(x))

using namespace std;

const int N = 1e5 + 5;

int n, m, a[N];

struct SegTree {
	int l, r, l0, l1, r0, r1, cnt1, mx0, mx1;
	int tag0, tag1, tag;
	SegTree friend operator +(SegTree a, SegTree b) {
		SegTree ret;
		ret.l = a.l;
		ret.r = b.r;
		ret.l0 = a.l0 + (a.l0 == a.r - a.l + 1 ? b.l0 : 0);
		ret.l1 = a.l1 + (a.l1 == a.r - a.l + 1 ? b.l1 : 0);
		ret.r0 = b.r0 + (b.r0 == b.r - b.l + 1 ? a.r0 : 0);
		ret.r1 = b.r1 + (b.r1 == b.r - b.l + 1 ? a.r1 : 0);
		ret.cnt1 = a.cnt1 + b.cnt1;
		ret.mx0 = max(max(a.mx0, b.mx0), a.r0 + b.l0);
		ret.mx1 = max(max(a.mx1, b.mx1), a.r1 + b.l1);
		return ret;
	}
}t[N << 2];
#define ls p << 1
#define rs p << 1 | 1

void build(int p, int l, int r) {
	t[p].l = l; t[p].r = r;
	t[p].tag = t[p].tag0 = t[p].tag1 = 0;
	if (l == r) {
		t[p].l0 = t[p].r0 = t[p].mx0 = !a[l];
		t[p].l1 = t[p].r1 = t[p].cnt1 = t[p].mx1 = a[l];
		return;
	}
	int mid = l + r >> 1;
	build(ls, l, mid);
	build(rs, mid + 1, r);
	t[p] = t[ls] + t[rs];
}

/*
l, r, l0, l1, r0, r1, cnt1, mx0, mx1;
tag0, tag1, tag;
*/

void spread(int p) {
	if (t[p].tag0) {
		t[ls].l0 = t[ls].r0 = t[ls].mx0 = t[ls].r - t[ls].l + 1;
		t[ls].l1 = t[ls].r1 = t[ls].cnt1 = t[ls].mx1 = 0;
		t[ls].tag0 = 1; t[ls].tag1 = t[ls].tag = 0;
		t[rs].l0 = t[rs].r0 = t[rs].mx0 = t[rs].r - t[rs].l + 1;
		t[rs].l1 = t[rs].r1 = t[rs].cnt1 = t[rs].mx1 = 0;
		t[rs].tag0 = 1; t[rs].tag1 = t[rs].tag = 0;
		t[p].tag0 = t[p].tag1 = t[p].tag = 0;
	}
	if (t[p].tag1) {
		t[ls].l1 = t[ls].r1 = t[ls].mx1 = t[ls].cnt1 = t[ls].r - t[ls].l + 1;
		t[ls].l0 = t[ls].r0 = t[ls].mx0 = 0;
		t[ls].tag1 = 1; t[ls].tag0 = t[ls].tag = 0;
		t[rs].l1 = t[rs].r1 = t[rs].mx1 = t[rs].cnt1 = t[rs].r - t[rs].l + 1;
		t[rs].l0 = t[rs].r0 = t[rs].mx0 = 0;
		t[rs].tag1 = 1; t[rs].tag0 = t[rs].tag = 0;
		t[p].tag0 = t[p].tag1 = t[p].tag = 0;		
	}
	if (t[p].tag) {
		swap(t[ls].l0, t[ls].l1);
		swap(t[ls].r0, t[ls].r1);
		swap(t[ls].mx0, t[ls].mx1);
		t[ls].cnt1 = t[ls].r - t[ls].l + 1 - t[ls].cnt1;
		if (t[ls].tag0) t[ls].tag0 = 0, t[ls].tag1 = 1;
		else if (t[ls].tag1) t[ls].tag0 = 1, t[ls].tag1 = 0;
		else t[ls].tag ^= 1;
		swap(t[rs].l0, t[rs].l1);
		swap(t[rs].r0, t[rs].r1);
		swap(t[rs].mx0, t[rs].mx1);
		t[rs].cnt1 = t[rs].r - t[rs].l + 1 - t[rs].cnt1;
		if (t[rs].tag0) t[rs].tag0 = 0, t[rs].tag1 = 1;
		else if (t[rs].tag1) t[rs].tag0 = 1, t[rs].tag1 = 0;
		else t[rs].tag ^= 1;
		t[p].tag = 0;
	}
}

void mdf(int p, int l, int r, int op) {
	spread(p);
	if (t[p].l >= l && t[p].r <= r) {
		if (op == 0) {
			t[p].l0 = t[p].r0 = t[p].mx0 = t[p].r - t[p].l + 1;
			t[p].l1 = t[p].r1 = t[p].cnt1 = t[p].mx1 = 0;
			t[p].tag0 = 1; t[p].tag1 = t[p].tag = 0;
		} else if (op == 1) {
			t[p].l1 = t[p].r1 = t[p].mx1 = t[p].cnt1 = t[p].r - t[p].l + 1;
			t[p].l0 = t[p].r0 = t[p].mx0 = 0;
			t[p].tag1 = 1; t[p].tag0 = t[p].tag = 0;
		} else {
			swap(t[p].l0, t[p].l1);
			swap(t[p].r0, t[p].r1);
			swap(t[p].mx0, t[p].mx1);
			t[p].cnt1 = t[p].r - t[p].l + 1 - t[p].cnt1;
			t[p].tag ^= 1;
		}
		return;
	}
	int mid = t[p].l + t[p].r >> 1;
	if (l <= mid) mdf(ls, l, r, op);
	if (r > mid) mdf(rs, l, r, op);
	t[p] = t[ls] + t[rs];
}

int qrycnt(int p, int l, int r) {
	spread(p);
	if (t[p].l >= l && t[p].r <= r) return t[p].cnt1;
	int mid = t[p].l + t[p].r >> 1, ret = 0;
	if (l <= mid) ret += qrycnt(ls, l, r);
	if (r > mid) ret += qrycnt(rs, l, r);
	return ret;
}

SegTree qrymx(int p, int l, int r) {
	spread(p);
	if (t[p].l >= l && t[p].r <= r) return t[p];
	SegTree ret; ret.l = -1;
	int mid = t[p].l + t[p].r >> 1;
	if (l <= mid) ret = qrymx(ls, l, r);
	if (r > mid) {
		if (ret.l == -1) ret = qrymx(rs, l, r);
		else ret = ret + qrymx(rs, l, r);
	}
	return ret;
}

signed main() {
    ios::sync_with_stdio(false);
	cin.tie(0); cout.tie(0);
	
	cin >> n >> m;
	for (int i = 1; i <= n; i++) cin >> a[i];
	build(1, 1, n);
	for (int i = 1, op, l, r; i <= m; i++) {
		cin >> op >> l >> r; l++; r++;
		if (op <= 2) mdf(1, l, r, op);
		else if (op == 3) cout << qrycnt(1, l, r) << '\n';
		else cout << qrymx(1, l, r).mx1 << '\n';
	}
    return 0;
}

在上面这份代码的mdf,qry函数中，我一开始写的是

if (t[p].l >= l && t[p].r <= r) ...
spread(p)

得了20pts ，改成

spread(p)
if (t[p].l >= l && t[p].r <= r) ...

就过了，但感觉好像差不多？救救孩子