之前用線段樹寫的，這次用splay寫了下。。

#include <cstdio>
#include <vector>
#include <algorithm>
#include <cstring>
using namespace std;

#define ll long long
#define lson tr[x][0]
#define rson tr[x][1]
const int maxn = 1e5 + 10;
const int INF = 1e9;
int root, tot;
int  fa[maxn], tr[maxn][2], sz[maxn];
ll tag[maxn], num[maxn], sum[maxn], a[maxn];

int judge(int x) {
    return tr[fa[x]][1] == x;
}

void pushup(int x) {
    if (x) {
        sz[x] = sz[tr[x][0]] + sz[tr[x][1]] + 1;
        sum[x] = sum[tr[x][0]] + sum[tr[x][1]] + num[x];
    }
}

void pushdown(int x) {
    if (tag[x]) {
        tag[lson] += tag[x];
        tag[rson] += tag[x];
        sum[lson] += (tag[x] * sz[lson]);
        sum[rson] += (tag[x] * sz[rson]);
        num[lson] += tag[x];
        num[rson] += tag[x];
        tag[x] = 0;
    }
}

void rotate(int x) {
    int y = fa[x], d = judge(x);
    if (tr[y][d] = tr[x][d ^ 1]) fa[tr[y][d]] = y;
    if (fa[x] = fa[y]) tr[fa[y]][judge(y)] = x;
    tr[fa[y] = x][d ^ 1] = y;
    pushup(y);
}

void splay(int x, int k) {
    for (int y; (y = fa[x]) != k; rotate(x))
        if (fa[y] != k) rotate(judge(x) == judge(y) ? y : x);
    pushup(x);
    if (!k) root = x;
}

int kth(int x, int k) {
    pushdown(x);
    if (sz[tr[x][0]] + 1 == k) return x;
    if (k <= sz[tr[x][0]]) return kth(tr[x][0], k);
    return kth(tr[x][1], k - 1 - sz[tr[x][0]]);
}


void update(int l, int r, int c) {
    int x = kth(root, l - 1);
    int y = kth(root, r + 1);
    splay(x, 0);
    splay(y, x);
    int rt = tr[y][0];
    tag[rt] += c;
    num[rt] += c;
    sum[rt] += (c * sz[rt]);
    pushup(y);pushup(x);
}

ll query(int l, int r) {
    int x = kth(root, l - 1);
    int y = kth(root, r + 1);
    splay(x, 0);
    splay(y, x);
    return sum[tr[y][0]];
}

void build(int &x, int l, int r) {
    if (l > r) {
        x = 0;
        return;
    }
    int mid = (l + r) / 2;
    x = ++tot;
    num[x] = a[mid];
    sz[x] = 1;
    tag[x] = sum[x] = 0;
    build(tr[x][0], l, mid - 1);
    build(tr[x][1], mid + 1, r);
    fa[tr[x][0]] = fa[tr[x][1]] = x;
    pushup(x);
}


int main() {
    int n, m, l, r, c;
    char op[10];
    while (scanf("%d%d", &n, &m) != EOF) {
        a[1] = a[n + 2] = 0;
        fa[1] = 0;
        for (int i = 2; i <= n + 1; i++) {
            scanf("%lld", &a[i]);
        }
        root = tot = 0;
        build(root, 1, n + 2);
        while (m--) {
            scanf("%s", op);
            if (op[0] == 'C') {
                scanf("%d%d%d", &l, &r, &c);
                l++; r++;
                update(l, r, c);
            }
            if (op[0] == 'Q') {
                scanf("%d%d", &l, &r);
                l++; r++;
                printf("%lld\n", query(l, r));
            }
        }
    }
    return 0;
}