自用

v1

#include <bits/stdc++.h>

#define l(p) (p << 1)
#define r(p) (p << 1 | 1)

using namespace std;
using ll = long long;

constexpr int N = 1e5 + 7;

int n, m, add[N << 2]; ll sum[N << 2];
void psu(int p) { sum[p] = sum[l(p)] + sum[r(p)]; }

void psd(int p, int l, int r) {
    if (add[p] && l != r) {
        add[l(p)] += add[p], add[r(p)] += add[p];
        int mid = (l + r) >> 1;
        sum[l(p)] += add[p] * (mid - l + 1);
        sum[r(p)] += add[p] * (r - mid);
        add[p] = 0;
    }
}

void upd(int p, int l, int r, int L, int R, ll x) {
    if (l >= L && r <= R) {
        add[p] += x, sum[p] += x * (r - l + 1);
        return;
    }
    psd(p, l, r);
    int mid = (l + r) >> 1;
    if (L <= mid) upd(l(p), l, mid, L, R, x);
    if (R > mid) upd(r(p), mid + 1, r, L, R, x);
    psu(p);
}

ll ask(int p, int l, int r, int L, int R) {
    if (l >= L && r <= R) return sum[p];
    psd(p, l, r);
    int mid = (l + r) >> 1; ll ans = 0;
    if (L <= mid) ans += ask(l(p), l, mid, L, R);
    if (R > mid) ans += ask(r(p), mid + 1, r, L, R);
    return ans;
}

v2

#include <bits/stdc++.h>

using ll = long long;

constexpr ll inf = 1e18;

struct segtree {
    int n;
    std::vector<ll> ad, mx;

    segtree(int sz) : ad((sz + 1) << 1), mx((sz + 1) << 1), n(sz) {}

    std::function<ll(ll, ll)> root = [&](ll l, ll r) {
        return l + r | l != r;
    };

    std::function<void(int, int, int)> pushup = [&](int l, int r, int mid) {
        ll p = root(l, r), pl = root(l, mid), pr = root(mid + 1, r);
        mx[p] = std::max(mx[pl], mx[pr]);
    };

    std::function<void(int, int)> pushdown = [&](int l, int r) {
        if (l == r || ad[root(l, r)] == 0) {
            return ;
        }

        ll mid = l + r >> 1;
        ll p = root(l, r), pl = root(l, mid), pr = root(mid + 1, r);
        ad[pl] += ad[p], ad[pr] += ad[p];
        mx[pl] += ad[p], mx[pr] += ad[p];
        ad[p] = 0;
    };

    std::function<void(int, ll)> modify = [&](int x, ll v) {
        ad[x << 1] += v;
        mx[x << 1] += v;
    };

    void add(int l, int r, int x, ll v) {
        if (l == r) {
            modify(x, v);
            return ;
        }

        pushdown(l, r);

        ll mid = l + r >> 1;
        if (x <= mid) {
            add(l, mid, x, v);
        } else {
            add(mid + 1, r, x, v);
        }

        pushup(l, r, mid);
    }

    void add(int x, ll v) {
        add(1, n, x, v);
    }

    ll max(int l, int r, int L, int R) {
        if (l >= L && r <= R) {
            return mx[root(l, r)];
        }

        pushdown(l, r);

        ll mid = l + r >> 1, res = -inf;
        if (L <= mid) {
            res = std::max(res, max(l, mid, L, R));
        }
        if (R > mid) {
            res = std::max(res, max(mid + 1, r, L, R));
        }
        
        return res;
    }
 
    ll max(int l, int r) {
        return max(1, n, l, r);
    }
};

jiangly's

from jiangly

#include <bits/stdc++.h>

using i64 = long long;

template<class Info, class Tag>
struct LazySegmentTree {
    int n;
    std::vector<Info> info;
    std::vector<Tag> tag;
    LazySegmentTree() : n(0) {}
    LazySegmentTree(int n_, Info v_ = Info()) {
        init(n_, v_);
    }
    template<class T>
    LazySegmentTree(std::vector<T> init_) {
        init(init_);
    }
    void init(int n_, Info v_ = Info()) {
        init(std::vector(n_, v_));
    }
    template<class T>
    void init(std::vector<T> init_) {
        n = init_.size();
        info.assign(4 << std::__lg(n), Info());
        tag.assign(4 << std::__lg(n), Tag());
        std::function<void(int, int, int)> build = [&](int p, int l, int r) {
            if (r - l == 1) {
                info[p] = init_[l];
                return;
            }
            int m = (l + r) / 2;
            build(2 * p, l, m);
            build(2 * p + 1, m, r);
            pull(p);
        };
        build(1, 0, n);
    }
    void pull(int p) {
        info[p] = info[2 * p] + info[2 * p + 1];
    }
    void apply(int p, const Tag &v) {
        info[p].apply(v);
        tag[p].apply(v);
    }
    void push(int p) {
        apply(2 * p, tag[p]);
        apply(2 * p + 1, tag[p]);
        tag[p] = Tag();
    }
    void modify(int p, int l, int r, int x, const Info &v) {
        if (r - l == 1) {
            info[p] = v;
            return;
        }
        int m = (l + r) / 2;
        push(p);
        if (x < m) {
            modify(2 * p, l, m, x, v);
        } else {
            modify(2 * p + 1, m, r, x, v);
        }
        pull(p);
    }
    void modify(int p, const Info &v) {
        modify(1, 0, n, p, v);
    }
    Info rangeQuery(int p, int l, int r, int x, int y) {
        if (l >= y || r <= x) {
            return Info();
        }
        if (l >= x && r <= y) {
            return info[p];
        }
        int m = (l + r) / 2;
        push(p);
        return rangeQuery(2 * p, l, m, x, y) + rangeQuery(2 * p + 1, m, r, x, y);
    }
    Info rangeQuery(int l, int r) {
        return rangeQuery(1, 0, n, l, r);
    }
    void rangeApply(int p, int l, int r, int x, int y, const Tag &v) {
        if (l >= y || r <= x) {
            return;
        }
        if (l >= x && r <= y) {
            apply(p, v);
            return;
        }
        int m = (l + r) / 2;
        push(p);
        rangeApply(2 * p, l, m, x, y, v);
        rangeApply(2 * p + 1, m, r, x, y, v);
        pull(p);
    }
    void rangeApply(int l, int r, const Tag &v) {
        return rangeApply(1, 0, n, l, r, v);
    }
    template<class F>
    int findFirst(int p, int l, int r, int x, int y, F pred) {
        if (l >= y || r <= x || !pred(info[p])) {
            return -1;
        }
        if (r - l == 1) {
            return l;
        }
        int m = (l + r) / 2;
        push(p);
        int res = findFirst(2 * p, l, m, x, y, pred);
        if (res == -1) {
            res = findFirst(2 * p + 1, m, r, x, y, pred);
        }
        return res;
    }
    template<class F>
    int findFirst(int l, int r, F pred) {
        return findFirst(1, 0, n, l, r, pred);
    }
    template<class F>
    int findLast(int p, int l, int r, int x, int y, F pred) {
        if (l >= y || r <= x || !pred(info[p])) {
            return -1;
        }
        if (r - l == 1) {
            return l;
        }
        int m = (l + r) / 2;
        push(p);
        int res = findLast(2 * p + 1, m, r, x, y, pred);
        if (res == -1) {
            res = findLast(2 * p, l, m, x, y, pred);
        }
        return res;
    }
    template<class F>
    int findLast(int l, int r, F pred) {
        return findLast(1, 0, n, l, r, pred);
    }
};

constexpr int inf = 1E9+1;
struct Min {
    int x = inf;
    void apply(Min t) & {
        x = std::min(x, t.x);
    }
};
Min operator+(Min a, Min b) {
    return {std::min(a.x, b.x)};
}