“1264. 动态求连续区间和”那题，发现自己写的代码有时超时过不了，代码如下

n,m = map(int,input().split())
lis = list(map(int,input().split()))
lis.insert(0,0)
class Node:
    def __init__(self):
        self.L = 0
        self.R = 0
        self.sum = 0
tr = [Node() for _ in range(100010*4)]

def pushup(x):
    tr[x].sum = tr[x << 1].sum + tr[x << 1 | 1].sum

def build(x,l,r):
    tr[x].L = l
    tr[x].R = r
    if l == r:
        tr[x].sum = lis[l]
    else:
        mid = l + r >> 1
        build(x << 1, l, mid)
        build(x << 1 | 1, mid + 1, r)
        pushup(x)

def query(x,l,r):
    if tr[x].L >= l and tr[x].R <= r:
        return tr[x].sum
    mid = tr[x].L + tr[x].R >> 1
    sum = 0
    if l <= mid:
        sum += query(x << 1, l, r)
    if r > mid:
        sum += query(x << 1 | 1, l, r)
    return sum

def modify(x,i,v):
    if tr[x].L == tr[x].R:
        tr[x].sum += v
    else:
        mid = tr[x].L + tr[x].R >> 1
        if i <= mid:
            modify(x << 1, i, v)
        else:
            modify(x << 1 | 1, i ,v)
        pushup(x)

build(1,1,n)

for i in range(m):
    k,a,b = map(int,input().split())
    if k == 0:
        print(query(1,a,b))
    else:
        modify(1,a,b)
    #print(tr[16].sum,tr[17].sum,tr[9].sum,tr[10].sum,tr[11].sum,tr[24].sum,tr[25].sum,tr[13].sum,tr[14].sum,tr[15].sum)

发现代码有时能过有时不能，为什么啊