PKU 3468 A Simple Problem with Integers

区间修改，询问，带有 lazy tag。

# include <stdio.h>

# define ls ((r) << 1)
# define rs ((r) << 1 | 1)
# define mid (((x)+(y))>>1)

# define MAXN 100005

typedef long long int LL;

int a[MAXN];
LL sum[MAXN * 4];
LL lazy[MAXN * 4];

void update(int r)
{
    sum[r] = sum[ls] + sum[rs];
}

void build(int x, int y, int r)
{
    sum[r] = 0;
    lazy[r] = 0;
    if (x == y)
    {
        sum[r] = a[x];
        return ;
    }
    build(x, mid, ls);
    build(mid+1, y, rs);
    update(r);
}

void pushdown(int x, int y, int r)
{
    if (lazy[r])
    {
        lazy[ls] += lazy[r], lazy[rs] += lazy[r];
        sum[ls] += lazy[r]*(mid-x+1);
        sum[rs] += lazy[r]*(y-mid);
        lazy[r] = 0;
    }
}

void add(int x, int y, int r, int s, int t, LL val)
{
    if (s<=x && y<=t)
    {
        lazy[r] += val;
        sum[r] += val*(y-x+1);
        return ;
    }
    pushdown(x, y, r);
    if (s<=mid) add(x, mid, ls, s, t, val);
    if (mid+1<=t) add(mid+1, y, rs, s, t, val);
    update(r);
}

void query(int x, int y, int r, int s, int t, LL *p)
{
    if (s<=x && y<=t)
    {
        *p += sum[r];
        return ;
    }
    pushdown(x, y, r);
    if (s<=mid) query(x, mid, ls, s, t, p);
    if (mid+1<=t) query(mid+1, y, rs, s, t, p);
}

int main()
{
    LL ans;
    char od[5];
    int i, n, m, s, t, val;
    
    while (~scanf("%d%d", &n, &m))
    {
        for (i = 1; i <= n; ++i) scanf("%d", &a[i]);
        build(1, n, 1);
        for (i = 1; i <= m; ++i)
        {
            scanf("%s%d%d", od, &s, &t);
            if (od[0] == 'C') scanf("%d", &val), add(1, n, 1, s, t, val);
            else ans = 0, query(1, n, 1, s, t, &ans), printf("%lld\n", ans);
        }
    }
    
    return 0;
}