CF 315B - Sereja and Array（树状数组）

水题，树状数组就行了。。。注意三种操作。。。

#include<iostream>
#include<cstring>
#include<cstdio>
#define FF(i, a, b) for(i = a; i <= b; i++)
#define FD(i, a, b) for(i = b; i >= a; i--)
#define CLR(a, b) memset(a, b, sizeof(a))
#define CPY(a, b) memcpy(a, b, sizeof(a))
#define LL __int64
using namespace std;
const int maxn = 1e5 +10;
LL n, m, c[maxn], cnt;

LL low(LL i) { return i & (-i);}

void add(LL i, LL p)
{
    while(i <= n)
    {
        c[i] += p;
        i += low(i);
    }
}

LL get(LL n)
{
    LL ret = 0;
    while(n > 0)
    {
        ret += c[n];
        n -= low(n);
    }
    return ret;
}

int main()
{
    while(~scanf("%I64d%I64d", &n, &m))
    {
        cnt = 0;
        CLR(c, 0);
        LL i, x, y, z;
        FF(i, 1, n)
        {
            scanf("%I64d", &x);
            add(i, x);
        }
        while(m--)
        {
            scanf("%I64d", &x);
            if(x == 1)
            {
                scanf("%I64d%I64d", &y, &z);
                LL tmp = get(y) - get(y-1);
                add(y, z-tmp-cnt);
            }
            else if(x == 2)
            {
                scanf("%I64d", &y);
                cnt += y;
            }
            else
            {
                scanf("%I64d", &y);
                printf("%I64d\n", get(y) - get(y-1) + cnt);
            }
        }
    }
    return 0;
}