区间求和，赋值，区间加，乘，最大值线段树

#include <bits/stdc++.h>
using namespace std;
#define int long long
#define endl '\n'
#define pii pair<int, int>
const int mod = 998244353;
const int inf = LLONG_MAX;
const int N = 5e5 + 100;

int n, m;
int a[N];

struct SegmentTree {
    int l, r;
    int mx;           // 区间最大值
    int sum;          // 区间和
    int add_lazy;     // 加法懒标记
    int mul_lazy;     // 乘法懒标记
    int set_lazy;     // 赋值懒标记 (inf表示未赋值)
} tr[N * 4];

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

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

// 核心：下传懒标记
void pushdown(int u) {
    int len_left = tr[u << 1].r - tr[u << 1].l + 1;
    int len_right = tr[u << 1 | 1].r - tr[u << 1 | 1].l + 1;
    
    // 优先级：赋值 > 乘法 > 加法
    if (tr[u].set_lazy != inf) {
        // 下传赋值标记
        int set_val = tr[u].set_lazy;
        
        tr[u << 1].mx = set_val;
        tr[u << 1].sum = set_val * len_left;
        tr[u << 1].set_lazy = set_val;
        tr[u << 1].add_lazy = 0;
        tr[u << 1].mul_lazy = 1;
        
        tr[u << 1 | 1].mx = set_val;
        tr[u << 1 | 1].sum = set_val * len_right;
        tr[u << 1 | 1].set_lazy = set_val;
        tr[u << 1 | 1].add_lazy = 0;
        tr[u << 1 | 1].mul_lazy = 1;
        
        tr[u].set_lazy = inf;
    }
    
    if (tr[u].mul_lazy != 1) {
        // 下传乘法标记
        int mul_val = tr[u].mul_lazy;
        
        tr[u << 1].mx *= mul_val;
        tr[u << 1].sum *= mul_val;
        tr[u << 1].mul_lazy *= mul_val;
        tr[u << 1].add_lazy *= mul_val;
        
        tr[u << 1 | 1].mx *= mul_val;
        tr[u << 1 | 1].sum *= mul_val;
        tr[u << 1 | 1].mul_lazy *= mul_val;
        tr[u << 1 | 1].add_lazy *= mul_val;
        
        tr[u].mul_lazy = 1;
    }
    
    if (tr[u].add_lazy != 0) {
        // 下传加法标记
        int add_val = tr[u].add_lazy;
        
        tr[u << 1].mx += add_val;
        tr[u << 1].sum += add_val * len_left;
        tr[u << 1].add_lazy += add_val;
        
        tr[u << 1 | 1].mx += add_val;
        tr[u << 1 | 1].sum += add_val * len_right;
        tr[u << 1 | 1].add_lazy += add_val;
        
        tr[u].add_lazy = 0;
    }
}

// 区间赋值操作
void set_range(int l, int r, int val, int u) {
    if (tr[u].l > r || tr[u].r < l) return;
    if (l <= tr[u].l && tr[u].r <= r) {
        tr[u].mx = val;
        tr[u].sum = val * (tr[u].r - tr[u].l + 1);
        tr[u].set_lazy = val;
        tr[u].add_lazy = 0;
        tr[u].mul_lazy = 1;
        return;
    }
    pushdown(u);
    int mid = (tr[u].l + tr[u].r) >> 1;
    if (l <= mid) set_range(l, r, val, u << 1);
    if (r > mid) set_range(l, r, val, u << 1 | 1);
    pushup(u);
}

// 区间加法操作
void add_range(int l, int r, int val, int u) {
    if (tr[u].l > r || tr[u].r < l) return;
    if (l <= tr[u].l && tr[u].r <= r) {
        tr[u].mx += val;
        tr[u].sum += val * (tr[u].r - tr[u].l + 1);
        tr[u].add_lazy += val;
        return;
    }
    pushdown(u);
    int mid = (tr[u].l + tr[u].r) >> 1;
    if (l <= mid) add_range(l, r, val, u << 1);
    if (r > mid) add_range(l, r, val, u << 1 | 1);
    pushup(u);
}

// 区间乘法操作
void mul_range(int l, int r, int val, int u) {
    if (tr[u].l > r || tr[u].r < l) return;
    if (l <= tr[u].l && tr[u].r <= r) {
        tr[u].mx *= val;
        tr[u].sum *= val;
        tr[u].mul_lazy *= val;
        tr[u].add_lazy *= val;
        return;
    }
    pushdown(u);
    int mid = (tr[u].l + tr[u].r) >> 1;
    if (l <= mid) mul_range(l, r, val, u << 1);
    if (r > mid) mul_range(l, r, val, u << 1 | 1);
    pushup(u);
}

// 区间最大值查询
int query_max(int l, int r, int u) {
    if (tr[u].l > r || tr[u].r < l) return -inf;
    if (l <= tr[u].l && tr[u].r <= r) return tr[u].mx;
    pushdown(u);
    int mid = (tr[u].l + tr[u].r) >> 1;
    int res = -inf;
    if (l <= mid) res = max(res, query_max(l, r, u << 1));
    if (r > mid) res = max(res, query_max(l, r, u << 1 | 1));
    return res;
}

// 区间和查询
int query_sum(int l, int r, int u) {
    if (tr[u].l > r || tr[u].r < l) return 0;
    if (l <= tr[u].l && tr[u].r <= r) return tr[u].sum;
    pushdown(u);
    int mid = (tr[u].l + tr[u].r) >> 1;
    int res = 0;
    if (l <= mid) res += query_sum(l, r, u << 1);
    if (r > mid) res += query_sum(l, r, u << 1 | 1);
    return res;
}

void solve() {
    cin >> n >> m;
    for (int i = 1; i <= n; i++) {
        cin >> a[i];
    }
    
    build(1, n, 1);
    
    while (m--) {
        int op, l, r, x;
        cin >> op;
        if (op == 1) {
            // 区间赋值
            cin >> l >> r >> x;
            set_range(l, r, x, 1);
        } else if (op == 2) {
            // 区间加法
            cin >> l >> r >> x;
            add_range(l, r, x, 1);
        } else if (op == 3) {
            // 区间乘法
            cin >> l >> r >> x;
            mul_range(l, r, x, 1);
        } else if (op == 4) {
            // 区间最大值查询
            cin >> l >> r;
            cout << query_max(l, r, 1) << endl;
        } else if (op == 5) {
            // 区间和查询
            cin >> l >> r;
            cout << query_sum(l, r, 1) << endl;
        }
    }
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    
    int t = 1;
    // cin >> t;  // 多组数据时取消注释
    while (t--) {
        solve();
    }
    return 0;
}