rt. 不理解.

编译显示：

Nothing is compiled: OUTPUT exceeds.

#include<bits/stdc++.h>
using namespace std;
const int N = 1e6 + 5;
int n,q,a[N];
struct node{
	int v = -1e9,d = 0,op = 0;
}t[N * 4];
void print(int x,int l,int r){
	printf("%d : %d %d %d %d\n",x,l,r,t[x].v,t[x].d);
	if(l == r) return;
	int mid = (l + r) >> 1;
	print(x << 1,l,mid);
	print(x << 1 | 1,mid + 1,r);
}
void build(int x,int l,int r){
	if(l == r){
		t[x].v = a[l];
		return;
	}
	int mid = (l + r) >> 1;
	build(x << 1,l,mid);
	build(x << 1 | 1,mid + 1,r);
	t[x].v = max(t[x << 1].v,t[x << 1 | 1].v);
}
void pushdown(int x,int l,int r){
	if(!t[x].op) return;
	t[x << 1].d = t[x].d,t[x << 1].op = t[x].op;
	t[x << 1 | 1].d = t[x].d,t[x << 1 | 1].op = t[x].op;
	if(t[x].op == 1){
		t[x << 1].v = t[x].v;
		t[x << 1 | 1].v = t[x].v;
	}
	else{
		t[x << 1].v += t[x].v;
		t[x << 1 | 1].v += t[x].v;
	}
	t[x].d = 0,t[x].op = 0;
}
void modify(int x,int l,int r,int ql,int qr,int v,int op){
	if(ql == l && r == qr){
		if(op == 1) t[x].v = v;
		else t[x].v += v;
		t[x].d = v,t[x].op = op;
		return;
	}
	pushdown(x,l,r);
	int mid = (l + r) >> 1;
	if(ql <= mid) modify(x << 1,l,mid,ql,min(mid,qr),v,op);
	if(qr > mid) modify(x << 1 | 1,mid + 1,r,max(mid + 1,ql),qr,v,op);
	t[x].v = max(t[x << 1].v,t[x << 1 | 1].v);
}
int query(int x,int l,int r,int ql,int qr){
	if(ql == l && qr == r)
        return t[x].v;
	pushdown(x,l,r);
	int mid = (l + r) >> 1,ans = -1e9;
	if(ql <= mid) ans = max(ans,query(x << 1,l,mid,ql,min(mid,qr)));
	if(qr > mid) ans = max(ans,query(x << 1 | 1,mid + 1,r,max(mid + 1,ql),qr));
	return ans;
}
int main(){
	scanf("%d%d",&n,&q);
	for(int i = 1;i <= n;i++)
		scanf("%d",&a[i]);
	build(1,1,n);
	while(q--){
		int op,l,r,v;
		scanf("%d%d%d",&op,&l,&r);
		if(op <= 2){
			scanf("%d",&v);
			modify(1,1,n,l,r,v,op);
		}
		else printf("%d\n",query(1,1,n,l,r));
		//print(1,1,n); printf("\n");
	}
	return 0;
}