알고리즘/알고리즘 문제
[백준] 2042. 구간 합 구하기
charminseok
2020. 9. 6. 19:37
세그먼트 트리 활용
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def seg_tree(nums, oper, b, c, tree):
def init(start, end, node, a, tree):
if start == end:
tree[node] = a[start]
return tree[node]
mid = (start+end)//2
tree[node] = init(start, mid, node*2, a, tree) + init(mid + 1, end, node * 2 + 1, a, tree)
return tree[node]
def sum(start,end,node,left,right, tree):
if left > end or right < start: return 0
if left <= start and end <= right: return tree[node]
mid = (start+end)//2
return sum(start, mid, node*2, left, right, tree) + sum(mid + 1, end, node*2+1, left, right, tree)
def update(start, end, node, index, dif, tree, a):
if index < start or index > end: return
if start == end:
tree[node] = dif
a[index] = dif
return
tree[node] += dif - a[index]
mid = (start+end) // 2
update(start,mid, node*2,index, dif, tree, a)
update(mid + 1, end, node*2 + 1,index, dif, tree, a)
S = 0
if oper == 0:
init(0, len(nums) - 1, 1, nums, tree)
elif oper == 1:
update(0, len(nums) - 1, 1, b-1, c, tree, nums)
else:
S = sum(0, len(nums)-1,1,b-1,c-1,tree)
return S
def sol():
n,m,k = map(int,input().split(' '))
num_list = []
for _ in range(n):
num_list.append(int(input()))
tree = [0]*4*len(num_list)
seg_tree(num_list, 0,0,0, tree)
for i in range(m+k):
a,b,c=map(int,input().split(' '))
S = seg_tree(num_list,a,b,c, tree)
if S != 0:
print(S)
sol()
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cs |