模板

#include<bits/stdc++.h>
using namespace std;
#define ls p<<1
#define rs p<<1|1
#define lson ls,l,mid
#define rson rs,mid+1,r
#define root 1,1,n
const int N = 1e6+9,mod = 1e9+7;
typedef long long ll;
int n,m,a[N];

struct tree
{
	int l,r,add,sum;

	tree()//需要写 不写不对 不知道为什么
	{
		l = r = sum = add = 0;
	}

	void col(int v)//打标记
	{

	}

}t[N<<2];

tree operator +(const tree &l,const tree &r)
{
	tree p;
	p.l = l.l;
	p.r = r.r;
	p.add = 0;//需要写 不写会乱标记 
	p.sum = l.sum + r.sum;

	return p;
}

void pushup(int p)
{
	t[p] = t[ls] + t[rs];
}

void pushdown(int p)
{
	int v = t[p].add;
	if(v)
	{
		t[ls].col(v);
		t[rs].col(v);
		t[p].add = 0;
	}
}

void build(int p,int l,int r)
{
	if(l == r)
	{
		t[p].l = t[p].r = l;
		t[p].col(a[l]);
		return;
	}
	int mid = (l+r)>>1;
	build(ls,l,mid);
	build(rs,mid+1,r);
	pushup(p);
}

void modify(int p,int l,int r,int L,int R,int v)
{
	if(L <= l && R >= r)
	{
		t[p].col(v);
		return;
	}
	pushdown(p);

	int mid = l+r>>1;
	if(l <= mid)modify(lson,L,R,v);
	if(r > mid)modify(rson,L,R,v);

	pushup(p);
}

tree query(int p,int l,int r,int L,int R)
{
	if(L <= l && R >= r)return t[p];
	pushdown(p);
	int mid = l+r>>1;
	if(r <= mid)return query(lson,L,R);
	else if(l > mid)return query(rson,L,R);
	else return query(lson,L,R) + query(rson,L,R);
}

int main()
{
	scanf("%d%d",&n,&m);

	for(int i = 1;i <= n;i++)scanf("%d",a+i);

	build(root);
	while(m--)
	{
		int op,l,r,v;
		scanf("%d%d%d",&op,&l,&r);
		if(op == 1)
		{
			scanf("%d",&v);
			modify(root,l,r,v);
		}
		else if(op == 2)
		{
			printf("%d",query(root,l,r).sum);
		}

	}

	return 0;
}