ABC190

It was 5 questions. (The top two are after the contest)

https://gyazo.com/9030631995d9ff9f43f12c962337334d

https://gyazo.com/058a608463f896cfd24f8e7fcce52025

It's a seemingly tricky problem, but since K is at most 16, it's not a problem to search 2^K times.

code:python

def main():

N, M = map(int, input().split())

AB = []

for _i in range(M):

A, B = map(int, input().split())

AB.append((A - 1, B - 1))

K = int(input())

CD = []

for _i in range(K):

C, D = map(int, input().split())

CD.append((C - 1, D - 1))

ret = 0

for i in range(2 ** K):

for j in range(K):

if i & 1:

else:

i >>= 1

r = 0

for j in range(M):

r += 1

ret = max(ret, r)

print(ret)

https://gyazo.com/ee1aa2792d7488de3ae51627cb8e6a45

Interesting question

That is, we can count the number of integers i,a such that [$ N = (i + 1) a + i (i + 1) / 2

$ 2N = 2a(i+1) + i(i+1) = (i + 1)(i + 2a)

code:python

def solve(N):

ret = 0

for x in get_divisors(2 * N):

if (2 * N // x - x + 1) % 2 == 0:

ret += 1

return ret

E

K as small as 17

Searching for a tree? Not necessarily a tree.

Depth-first tracing is not optimal.

Minimum number of moves to follow the graph?

DP？

Once you see F first

https://gyazo.com/62384af9136737b3adf36fccca4e1237

I tried to update the difference with a phoenix tree, but when I thought about the update part carefully, I didn't need the phoenix tree operation.

Only use it where you seek it first.

Removing the leading x reduces the number of falls by the number of those less than x

Since it is sorted from 0 to N-1, it is x

Adding x at the end increases the number of tumbles by the number of things larger than x

N-1-x

code:python

def main():

N = int(input())

AS = list(map(int, input().split()))

ft = FenwickTree(size=N)

tento = 0

for i in range(N):

for i in range(N):

print(tento)

tento -= x

tento += (N - 1 - x)

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