不知道线段树哪里有问题？10$pts$

#include<bits/stdc++.h>
#define ll long long
#define maxn 1000001
using namespace std;
ll ans[maxn<<2], lazy[maxn<<2];
ll a[maxn];

void Sum(ll x) {
	ans[x] = ans[x<<1] + ans[(x<<1)|1];
}

void build(int l, int r, ll x) {
	if(l==r) {
		ans[l] = a[x];
		return;		
	}
	int mid=(l+r)>>1;
	build(l, mid, x<<1);
	build(mid+1, r, (x<<1)|1);
	Sum(x);
}

void update1(int l, int r, int s, int t, ll x, int c) {
	if(l<=s and t<=r) {
		ans[x] += (t-s+1) * c;
		lazy[x] += c;
		return;
	}
	int mid=(s+t)>>1;
	if(lazy[x] and s!=t) {
		ans[x<<1] += (mid-s+1) * lazy[x];
		ans[(x<<1)|1] += (t-mid) * lazy[x];
		lazy[x<<1] += lazy[x];
		lazy[(x<<1)|1] += lazy[x];
		lazy[x] = 0;
	}
	if(l<=mid) update1(l, r, s, mid, x<<1, c);
	if(r>mid) update1(l, r, mid+1, t, (x<<1)|1, c);
	Sum(x);
}

void update2(int l, int r, int s, int t, ll x, int c) {
	if(l<=s and t<=r) {
		ans[x] = (t-s+1) * c;
		lazy[x] = c;
		return;
	}
	int mid=(s+t)>>1;
	if(lazy[x] and s!=t) {
		ans[x<<1] = c * (mid-s+1);
		ans[(x<<1)|1] = c * (t-mid);
		lazy[x<<1] = lazy[(x<<1)|1] = c;
	} 
	if(l<=mid) update2(l, r, s, mid, x<<1, c);
	if(r>mid) update2(l, r, mid+1, t, (x<<1)|1, c);
	Sum(x);
}

ll getsum(int l, int r, int s, int t, ll x) {
	if(l<=s and t<=r) {
		return ans[x];
	}
	int mid=(s+t)>>1;
	if(lazy[x]) {
		ans[x<<1] += lazy[x] * (mid-s+1);
		ans[(x<<1)|1] += lazy[x] * (t-mid);
		lazy[x<<1] += lazy[x];
		lazy[(x<<1)|1] += lazy[x];
		lazy[x] = 0;
	}
	ll sum = 0;
	if(l<=mid) sum = getsum(l, r, s, mid, x<<1);
	if(r>mid) sum += getsum(l, r, mid+1, t, (x<<1)|1);
	return sum;
}

int n, q;
int main(void) {
	ios::sync_with_stdio(false);
	cin.tie(0), cout.tie(0);
	cin >> n >> q;
	for(int i=1; i<=n; i++) {
		cin >> a[i];
	}
	build(1, n, 1);
	for(int i=1, opt, l, r, x; i<=q; i++) {
		cin >> opt;
		if(opt==1) {
			cin >> l >> r >> x;
			update2(l, r, 1, n, 1, x);
		}
		if(opt==2) {
			cin >> l >> r >> x;
			update1(l, r, 1, n, 1, x);
		}
		if(opt==3) {
			cin >> l >> r;
			cout << getsum(l, r, 1, n, 1) << endl;
		}
	}
	return 0;
}