60求调 爹们看看

#include <iostream>
#include <algorithm>
using namespace std;
const int N = 1e6 + 10;
typedef long long LL;
int n, m;

struct Node
{
    int l, r;
    LL add, change ,maxv;
}tr[N * 4];
LL a[N];
bool st = false;

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

void pushdown(int u)
{
    Node& root = tr[u], &left = tr[u << 1], &right = tr[u << 1 | 1];

    if (root.add != 0)
    {
        left.add += root.add, left.maxv += root.add;
        right.add += root.add, right.maxv += root.add;
        root.add = 0;
    }
    if (st == true)
    {
        left.change = root.change, left.maxv = root.change;
        right.change = root.change, right.maxv = root.change;
        st = false;
    }
}

void modify(int u, int l, int r, int x)
{
    if (tr[u].l >= l && tr[u].r <= r)
    {
        tr[u].maxv += x;
        tr[u].add += x;
    }
    else
    {
        st = false;
        pushdown(u);
        int mid = tr[u].l + tr[u].r >> 1;
        if (l <= mid) modify(u << 1, l, r, x);
        if (r > mid) modify(u << 1 | 1, l, r, x);
        pushup(u);
    }
}

void cmodify(int u, int l, int r, int x)
{
    if (tr[u].l >= l && tr[u].r <= r)
    {
        tr[u].maxv = x;
        tr[u].change = x;
        tr[u].add = 0;
    }
    else
    {
        st = true;
        tr[u].add = 0;
        pushdown(u);
        int mid = tr[u].l + tr[u].r >> 1;
        if (l <= mid) cmodify(u << 1, l, r, x);
        if (r > mid) cmodify(u << 1 | 1, l, r, x);
        pushup(u);
    }
}

LL query(int u, int l, int r)
{
    if (tr[u].l >= l && tr[u].r <= r)
        return tr[u].maxv;

    pushdown(u);
    LL maxn = -1e17;
    int mid = tr[u].l + tr[u].r >> 1;
    if (l <= mid) maxn = max(maxn , query(u << 1, l, r));
    if (r > mid) maxn = max(maxn, query(u << 1 | 1, l, r));
    return maxn;
}

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

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, x;
        scanf("%d", &op);
        if (op == 1)
        {
            scanf("%d%d%d", &l, &r, &x);
            cmodify(1, l, r, x);
        }
        else if (op == 2) {
            scanf("%d%d%d", &l, &r, &x);
            modify(1, l, r, x);
        }
        else
        {
            scanf("%d%d", &l, &r);
            printf("%lld\n" , query(1, l, r));
        }
    }
    return 0;
}