线段树模板

昨天又刷了一遍线段树的基础题，复习了一下模板，贴出来以便以后复习。

#include <iostream>
#include <cstdio>
#include <cstring>
#define mid ((l + r) >> 1)
#define lson id << 1
#define rson id << 1 | 1

using namespace std;

long long sum[1000010], lazy[1000010];

inline void PushUp(int id)
{
    sum[id] = sum[lson] + sum[rson];
}

void Build(int l, int r, int id)
{
    if(l == r)
    {
        scanf("%lld", &sum[id]);
        return ;
    }
    Build(l, mid, lson);
    Build(mid + 1, r, rson);
    PushUp(id);
}

void PushDown(int id, int num)
{
    lazy[lson] += lazy[id];
    lazy[rson] += lazy[id];
    sum[lson] += (num - num / 2) * lazy[id];
    sum[rson] += (num / 2) * lazy[id];
    lazy[id] = 0;
}

void Update(int l, int r, int id, int cl, int cr, long long v)
{
    if(l > cr || r < cl)
        return ;
    if(lazy[id])
        PushDown(id, r - l + 1);
    if(l >= cl && r <= cr)
    {
        sum[id] += (r - l + 1) * v;
        lazy[id] += v;
        return ;
    }
    Update(l, mid, lson, cl, cr, v);
    Update(mid + 1, r, rson, cl, cr, v);
    PushUp(id);
}

long long QuerySum(int l, int r, int id, int ql, int qr)
{
    if(l > qr || r < ql)
        return 0;
    if(lazy[id])
        PushDown(id, r - l + 1);
    if(l >= ql && r <= qr)
        return sum[id];
    return QuerySum(l, mid, lson, ql, qr) + QuerySum(mid + 1, r, rson, ql, qr);
}

int main()
{
    int n, optimes;
    long long add;
    char c;
    while(~scanf("%d %d", &n, &optimes))
    {
        memset(sum, 0, sizeof(sum));
        memset(lazy, 0, sizeof(lazy));
        Build(1, n, 1);
        getchar();
        int l, r;
        while(optimes --)
        {
            scanf("%c", &c);
            if(c == 'Q')
            {
                scanf("%d %d", &l, &r);
                printf("%lld\n", QuerySum(1, n, 1, l, r));
            }
            if(c == 'C')
            {
                scanf("%d %d %lld", &l, &r, &add);
                Update(1, n, 1, l, r, add);
            }
            getchar();
        }
    }
    return 0;
}