线段树模板

找了个舒服的线段树模板

详细请见原作者：

https://zhuanlan.zhihu.com/p/106118909

 

 

 

 

 

 

 

模板代码：

#include <bits/stdc++.h>
#define MAXN 100005
using namespace std;
typedef long long ll;
ll n, m, A[MAXN]; 
ll tree[MAXN * 4];//各个节点的值 
ll mark[MAXN * 4];//懒标记 
// 经验表明开四倍空间不会越界
inline void push_down(ll p, ll len)//将当前节点的懒标记下推并且将当前节点的懒标记清除 
{
    mark[p * 2] += mark[p];
    mark[p * 2 + 1] += mark[p];
    tree[p * 2] += mark[p] * (len - len / 2);
    tree[p * 2 + 1] += mark[p] * (len / 2);
    mark[p] = 0;
}

void build(ll l = 1, ll r = n, ll p = 1)
{
    if (l == r)
        tree[p] = A[l];
    else
    {
        ll mid = (l + r) / 2;
        build(l, mid, p * 2);
        build(mid + 1, r, p * 2 + 1);
        tree[p] = tree[p * 2] + tree[p * 2 + 1];
    }
}

void update(ll l, ll r, ll d, ll p = 1, ll cl = 1, ll cr = n)
{
    if (cl > r || cr < l)
        return;
    else if (cl >= l && cr <= r)
    {
        tree[p] += (cr - cl + 1) * d;
        if (cr > cl)
            mark[p] += d;
    }
    else
    {
        ll mid = (cl + cr) / 2;
        push_down(p, cr - cl + 1);
        update(l, r, d, p * 2, cl, mid);
        update(l, r, d, p * 2 + 1, mid + 1, cr);
        tree[p] = tree[p * 2] + tree[p * 2 + 1];
    }
}

ll query(ll l, ll r, ll p = 1, ll cl = 1, ll cr = n)
{
    if (cl > r || cr < l)
        return 0;
    else if (cl >= l && cr <= r)
        return tree[p];
    else
    {
        ll mid = (cl + cr) / 2;
        push_down(p, cr - cl + 1);
        return query(l, r, p * 2, cl, mid) + query(l, r, p * 2 + 1, mid + 1, cr);
    }
}

int main()
{
    cin>>n;
    cin>>m;
    for (int i = 1; i <= n; i++)
        cin>>A[i];
    build();
    for (int i = 1; i <= m; i++)
    {
        ll opr,l,r;
        cin>>opr>>l>>r;
        if (opr == 1)
        {
            ll d;
            cin>>d;
            update(l, r, d);
        }
        else
            cout<<query(l, r)<<endl;
    }
    return 0;
}