原题链接：https://www.acwing.com/problem/content/244/

线段树模板

#include <iostream>

#define ll long long

const ll N = 1e6;

struct ii{
    ll l;
    ll r;
    ll v;
    ll less;
}tree[N * 4];
ll op[N];

void pushup(ll xx){//向上遍历
    tree[xx].v = tree[xx * 2].v + tree[xx * 2 + 1].v;
}

void pushdown(ll xx){//向下遍历
    tree[xx * 2].v += tree[xx].less * (tree[xx * 2].r - tree[xx * 2].l + 1);
    tree[xx * 2 + 1].v += tree[xx].less * (tree[xx * 2 + 1].r - tree[xx * 2 + 1].l + 1);
    tree[xx * 2].less += tree[xx].less;
    tree[xx * 2 + 1].less += tree[xx].less;
    tree[xx].less = 0;
    return ;
}

void built(ll l,ll r,ll x){//建树
    if(l == r){
        tree[x] = {l,r,op[l]};
        return ;
    } else{
        tree[x] = {l,r};
    }
    ll mid = (l + r) / 2;
    built(l,mid,x * 2);
    built(mid + 1,r,x * 2 + 1);
    pushup(x);//向上延伸
}

ll serch(ll aa,ll bb,ll cc){//求区域的和
    if(tree[cc].l >= aa && tree[cc].r <= bb){
        return tree[cc].v;
    }
    pushdown(cc);
    ll mid = (tree[cc].l + tree[cc].r) / 2;
    ll res = 0;
    if(aa <= mid) res += serch(aa,bb,cc * 2);
    if(bb > mid) res += serch(aa,bb,cc * 2 + 1);
    return res;
}

void check(ll xx,ll aa,ll bb,ll cc){//改变数组当中的值
    if(tree[xx].l >= aa && tree[xx].r <= bb){
        tree[xx].v += (tree[xx].r - tree[xx].l + 1) * cc;
        tree[xx].less += cc;
        return ;
    }
    pushdown(xx);
    ll mid = (tree[xx].l + tree[xx].r) / 2;
    if(aa <= mid) check(xx * 2,aa,bb,cc);
    if(bb > mid) check(xx * 2 + 1,aa,bb,cc);
    pushup(xx);
    return ;
}

void solve(){
    ll n,m;
    std::cin >> n >> m;
    for(ll i = 1; i <= n; i ++) std::cin >> op[i];
    built(1,n,1);
    while(m --){
        char a;
        ll aa,bb,cc;
        std::cin >> a;
        if(a == 'Q'){//求和
            std::cin >> aa >> bb;
            std::cout << serch(aa,bb,1) << "\n";
        } else{
            std::cin >> aa  >> bb >> cc;
            check(1,aa,bb,cc);
        }
    }
}

int main(){
    ll t = 1;
//  std::cin >> t;
    while(t --)
    solve();
    return 0;
}