今天把这题搞完再AFO了

#include <bits/stdc++.h>
using namespace std;
#define lk k<<1
#define rk k<<1|1
#define mlr l+r>>1
typedef long long ll;
const int N = 1e5 + 5;
int a[N], num[4 * N], add[4 * N];
struct node {
	int l, mid, r;
}mx[4 * N], mx0[4 * N];//储存最长1，最长0
void swap(int& a, int& b) { a = a + b; b = a - b; a = a - b; }
void pushup(int k, int l, int r) {
	/*
	mx[k].l = mx[lk].l; mx[k].r = mx[rk].r;
	mx[k].mid = max(mx[lk].r + mx[rk].l, max(mx[lk].mid, mx[rk].mid));
	mx0[k].l = mx0[lk].l; mx0[k].r = mx0[rk].r;
	mx0[k].mid = max(mx0[lk].r + mx0[rk].l, max(mx0[lk].mid, mx0[rk].mid));
	return;
	*/
	//但是这部分是错的。
}
void modify(int k, int l, int r, int v) {
	//pushup(k, l, r);
	if (v == -1) { num[k] = 0;  mx[k].l = mx[k].mid = mx[k].r = 0; mx0[k].l = mx0[k].mid = mx0[k].r = (r - l + 1);
	}
	if (v == 1) { num[k] = (r - l + 1);  mx[k].l = mx[k].mid = mx[k].r = (r - l + 1); mx0[k].l = mx0[k].mid = mx0[k].r = 0;
	}
	if (v == 2) {
		num[k] = (r - l + 1) - num[k]; 
		swap(mx[k].l, mx0[k].l);
		swap(mx[k].mid, mx0[k].mid);
		swap(mx[k].r, mx0[k].r);
	}
	add[k] = v;
}

void pushdown(int k, int l, int r, int mid) {
	if (add[k] != 0) {
		modify(lk, l, mid, add[k]);
		modify(rk, mid + 1, r, add[k]);
		add[k] = 0;
	}
}
void build(int k, int l, int r) {
	if (l == r) {
		num[k] = a[l];
		mx[k].l = mx[k].r = mx[k].mid = a[l];
		mx0[k].l = mx0[k].r = mx0[k].mid = (1-a[l]);
		return;
	}
	int mid = mlr;
	build(lk, l, mid); build(rk, mid + 1, r);
	num[k] = num[lk] + num[rk];
	pushup(k, l, r);
}
void update(int k, int l, int r, int x, int y, int v) {
	if (l > y || r < x) {
		return;
	}//-1->0 1->1 2->fanzhuan
	if (l >= x && r <= y) {
		
		modify(k, l, r, v);
		return;
	}
	int mid = mlr;
	pushdown(k, l, r, mid);
	update(lk, l, mid, x, y, v); update(rk, mid + 1, r, x, y, v);
	num[k] = num[lk] + num[rk];
	pushup(k, l, r);
}
ll query(int k,int l,int r,int x,int y){
	if (l > y || r < x)return 0;
	if (l >= x && r <= y) {
		return num[k];
	}
	int mid = mlr;
	pushdown(k, l, r, mid);
	return query(lk, l, mid, x, y) + query(rk, mid + 1, r, x, y);
}
node querymx(int k, int l, int r, int x, int y) {
	if (l > y || r < x)return {0,0,0};
	if (l >= x && r <= y) {
		return mx[k];
	}
	int mid = mlr;
	pushdown(k, l, r, mid);
	node t1=querymx(lk, l, mid, x, y),t2=querymx(rk, mid + 1, r, x, y);
	
	node tmp;
	tmp.l = t1.l, tmp.r = t2.r;
	tmp.mid = max(t1.r + t2.l, max(t1.mid, t2.mid));
	return tmp;
}

int n, m,l,r,opt;
node t;
int main() {
	scanf("%d%d", &n, &m);
	for (int i = 1; i <= n; i++) {
		scanf("%d", &a[i]);
	}
	build(1, 1, n);
	while (m--) {
		scanf("%d%d%d", &opt, &l, &r);
		l++, r++;
		switch (opt){
			case 0:
				update(1, 1, n, l, r, -1);
				break;
			case 1:
				update(1, 1, n, l, r, 1);
				break;
			case 2:
				update(1, 1, n, l, r, 2);
				break;
			case 3:
				printf("%d\n", query(1, 1, n, l, r));
				break;
			case 4:
				t = querymx(1, 1, n, l, r);
				printf("%d\n",max(t.mid,max(t.l,t.r)));
				break;
			default:
				break;

		}
	}
}