萌新刚学OI1ms,线段树求助

#include<bits/stdc++.h>
using namespace std;
const int maxn=1e5+10;
int n,m,a[maxn],tree[maxn*4];
int lzy[maxn*4]; 
void pushup(int u){
	tree[u]=tree[u*2]+tree[u*2+1];
}
void build(int u,int left,int right){
	if(left==right){
		tree[u]=a[left];
		return;
	}
	int mid=(left+right)/2;
	build(u*2,left,mid);
	build(u*2+1,mid+1,right);
	pushup(u);
	return;
}
bool intheline(int L,int R,int l,int r){
	return l<=L&&r>=R;
}
bool cdline(int L,int R,int l,int r){
	return L<=r&&R>=l;
}
int sum(int u,int left,int right,int l,int r){
	if(intheline(left,right,l,r)) return tree[u];
	else if(cdline(left,right,l,r)){
		int mid=(left+right)/2;
		return sum(u*2,left,mid,l,r)+sum(u*2+1,mid+1,right,l,r);
	}
	return 0;
}
void make(int u,int k,int len){
	lzy[u]+=k;
	tree[u]+=len*k;
	return;
}
void pushdown(int u,int left,int right){
	int mid=(left+right)/2;
	make(u*2,lzy[u],mid-left+1);
	make(u*2+1,lzy[u],right-mid);
	lzy[u]=0;
	return;
}
/*
void printt(int u){
	if(u>2*n-1) return;
	cout << tree[u] << " ";
	printt(u*2);
	printt(u*2+1);
}
*/
void update(int u,int left,int right,int l,int r,int k){
	if(intheline(left,right,l,r)){
		make(u,k,right-left+1);
		return;
	}else if(cdline(left,right,l,r)){
		int mid=(left+right)/2;
		pushdown(u,left,right);
		update(u*2,left,mid,l,r,k);
		update(u*2+1,mid+1,right,l,r,k);
		pushup(u);
	}else return;
}
int main(){
	cin >> n >> m;
	for(int i=1;i<=n;i++) scanf("%d",&a[i]);
	build(1,1,n);
	for(int i=1;i<=m;i++){
		int opt,x,y;
		cin >> opt >> x >> y;
		if(opt==1){
			int k;
			cin >> k;
			update(1,1,n,x,y,k);
		}else{
		    printf("%d\n",sum(1,1,n,x,y));
		}
	}
	return 0;
}