A Simple Problem with Integers(线段树)

http://poj.org/problem?id=3468

题意：就是区间的查询与更新。。

#include <stdio.h>
#include <string.h>
const int maxn=100010;
const int maxm=6600000;
#define LL long long
struct node
{
    int a,b;
    int l,r;
    LL  sum;
    LL  h;
} A[maxm];
int Num[maxn],cnt;
void build(int root)
{
    int a = A[root].a;
    int b = A[root].b;
    int mid = (a+b)>>1;
    A[root].h = 0;
    if (a==b)
    {
        A[root].sum = Num[a];
        return ;
    }
    int l = ++cnt;
    int r = ++cnt;
    A[l].a = a;
    A[l].b = mid;
    A[r].a = mid+1;
    A[r].b = b;
    build(l);
    build(r);
    A[root].sum = A[l].sum+A[r].sum;
    A[root].l = l;
    A[root].r = r;
}
LL Query(int t,int a1,int b1,LL h)
{
    int a = A[t].a;
    int b = A[t].b;
    int mid = (a+b)>>1;
    if (a==a1&&b==b1)
        return A[t].sum+(b1-a1+1)*h;
    if (b1 <= mid)
        return Query(A[t].l,a1,b1,A[t].h+h);
    if (a1 > mid)
        return Query(A[t].r,a1,b1,A[t].h+h);
    LL suml = Query(A[t].l,a1,mid,A[t].h+h);
    LL sumr = Query(A[t].r,mid+1,b1,A[t].h+h);
    return suml+sumr;
}
void Update(int t,int a1,int b1,int c)
{
    int a = A[t].a;
    int b = A[t].b;
    int l = A[t].l;
    int r = A[t].r;
    int mid = (a+b)>>1;
    A[t].sum += (b1-a1+1)*c;
    if (a==a1&&b==b1)
    {
        A[t].h+=c;
        return ;
    }
    if (b1 <= mid)
        Update(l,a1,b1,c);
    else if (a1 > mid)
        Update(r,a1,b1,c);
    else
    {
        Update(l,a1,mid,c);
        Update(r,mid+1,b1,c);
    }
}
int main()
{
    int N,Q,a,b,c;
    char s[3];
    cnt = 0;
    scanf("%d%d",&N,&Q);
    for (int i = 1; i <= N; i++)
        scanf("%d",&Num[i]);
    getchar();
    int t = ++cnt;
    A[t].a = 1;
    A[t].b = N;
    build(t);
    while(Q--)
    {
        scanf("%s",s);
        if (s[0]=='Q')
        {
            scanf("%d%d",&a,&b);
            printf("%lld\n",Query(1,a,b,0));
        }
        else
        {
            scanf("%d%d%d",&a,&b,&c);
            Update(1,a,b,c);
        }
    }
    return 0;
}