Wrong Answer，已经自己调了很久了，求助！！！

#include <iostream>
#include <cstdio>
#include <algorithm>

using namespace std;

typedef long long ll;

const int N = 1000010;
const ll inf = 1e18;

int n, m;
ll a[N];
struct Node
{
    int l, r;
    ll maxv, add, tag;
}tr[N << 2];

inline void pushup(int u)
{
    tr[u].maxv = max(tr[u << 1].maxv, tr[u << 1 | 1].maxv);
}

//先下传tag再add
inline void pushdown(int u)
{
    if (tr[u].tag != inf )
    {
        
        tr[u << 1].maxv = tr[u].tag;
        tr[u << 1].add = 0;
        tr[u << 1].tag = tr[u].tag;
        tr[u << 1 | 1].maxv = tr[u].tag;
        tr[u << 1 | 1].add = 0;
        tr[u << 1 | 1].tag = tr[u].tag;
        tr[u].tag = inf;
    }
    else if (tr[u].add != 0 )
    {
        if ( tr[u << 1].tag != inf &&  tr[u << 1 | 1].tag != inf) {
           tr[u << 1].maxv += tr[u].add;
           tr[u << 1].add = 0;
           tr[u << 1].tag += tr[u].add;
           tr[u << 1 | 1].maxv += tr[u].add;
           tr[u << 1 | 1].add = 0;
           tr[u << 1 | 1].tag += tr[u].add; 
        }
        else {
          tr[u << 1].maxv += tr[u].add;
          tr[u << 1].add += tr[u].add;
          tr[u << 1].tag = inf;
          tr[u << 1 | 1].maxv += tr[u].add;
          tr[u << 1 | 1].add += tr[u].add;
          tr[u << 1 | 1].tag = inf;  
        }
        
        /*tr[u << 1].maxv += tr[u].add;
        tr[u << 1].add += tr[u].add;
        tr[u << 1].tag = inf;
        tr[u << 1 | 1].maxv += tr[u].add;
        tr[u << 1 | 1].add += tr[u].add;
        tr[u << 1 | 1].tag = inf; */
        tr[u].add = 0;   
    }
}

inline void build(int u, int l, int r)
{
    if (l == r) tr[u] = {l, r, a[r], 0, inf};
    else
    {
        tr[u] = {l, r, 0, 0, inf};  //tr[u].l = l, tr[u].r = r;
        int mid = l + r >> 1;
        build(u << 1, l, mid), build(u << 1 | 1, mid + 1, r);
        pushup(u);
    }
}

inline void modify1(int u, int l, int r,  ll tag) {
    //tr[u].add = 0;
    
    if (tr[u].l >= l && tr[u].r <= r)
    {
        if ( tr[u].add != 0 ) {
        	tr[u].add = 0;
		}
		
		tr[u].maxv = tag, tr[u].tag = tag; // + tr[u].add = 0, 
    }
    else
    {
        int mid = tr[u].l + tr[u].r >> 1;
        pushdown(u);
        if (l <= mid) modify1(u << 1, l, r,  tag);
        if (r > mid) modify1(u << 1 | 1, l, r,  tag);
        pushup(u);
    }
}

inline void modify2(int u, int l, int r, ll add)
{
    if (tr[u].l >= l && tr[u].r <= r)
    {    
         if ( tr[u].tag != inf) {
         	tr[u].tag += add, tr[u].maxv += add, tr[u].add = 0;
		 }
         else tr[u].maxv += add, tr[u].add += add;
    }
    else
    {
        int mid = tr[u].l + tr[u].r >> 1;
        pushdown(u);
        if (l <= mid) modify2(u << 1, l, r, add);
        if (r > mid) modify2(u << 1 | 1, l, r, add);
        pushup(u);
    }
}

/* inline void modify(int u, int l, int r, ll add, ll tag)
{
    if (tr[u].l >= l && tr[u].r <= r)
    {
        if (add) tr[u].maxv += add, tr[u].add += add;
        else tr[u].maxv = tag, tr[u].tag = tag; // + tr[u].add = 0, 
    }
    else
    {
        int mid = tr[u].l + tr[u].r >> 1;
        pushdown(u);
        if (l <= mid) modify(u << 1, l, r, add, tag);
        if (r > mid) modify(u << 1 | 1, l, r, add, tag);
        pushup(u);
    }
}  */
 
inline ll query(int u, int l, int r)
{
    if (tr[u].l >= l && tr[u].r <= r) return tr[u].maxv;
    int mid = tr[u].l + tr[u].r >> 1;
    ll res = -inf;
    pushdown(u);
    if (r <= mid)  res =  query(u << 1, l, r);
    else if (l > mid)   res = query(u << 1 | 1, l, r);
    else res = max (query(u << 1, l, r), query(u << 1 | 1, l, r) );
    
    //if (l <= mid) res = max(res, query(u << 1, l, r)) ;
    //if (r > mid) res = max(res, query(u << 1 | 1, l, r));
    return res;
}

int main()
{
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= n; i ++ ) scanf("%lld", &a[i]);
    build(1, 1, n);
    while (m -- )
    {
        int op, l, r;
        ll x;
        scanf("%d%d%d", &op, &l, &r);
        if (op == 1)  
           {scanf("%lld", &x), modify1(1, l, r,  x);
            //for (int i = 1; i <= n; i ++ )  cout <<  a[i] << "  "; 
            //cout << endl;
           }
        
        else if (op == 2)  
          { scanf("%lld", &x), modify2(1, l, r, x);
            //for (int i = 1; i <= n; i ++ )  cout <<  a[i] << "  ";
            //cout <<  endl;
              }
          
          
        else printf("%lld\n", query(1, l, r));
    }
    return 0;
}

如果帮忙调出来真的非常感谢！