AtCoder Beginners Contest Past Question Challenge 4

AtCoder Beginners Contest Past Question Challenge 4

ABC126D - Even Relation

Find the distances from vertex 1 for all vertices in the search, and output 0 for even-numbered vertices and 1 for odd-numbered vertices.

N = int(input())

link = [[] for _ in range(N)]
for _ in range(N - 1):
    u, v, w = map(int, input().split())
    link[u - 1].append((v - 1, w))
    link[v - 1].append((u - 1, w))

d = [-1] * N
d[0] = 0
q = [0]
while q:
    p = q.pop()
    for n, w in link[p]:
        if d[n] == -1:
            d[n] = d[p] + w
            q.append(n)

for i in d:
    print(i % 2)

ABC126E - 1 or 2

"A X i </ sub> </ sub> + A Y i </ sub> </ sub> + Z i </ sub> is an even number "." Means that if you know one A, you know the other. If "A X </ sub> + A Y </ sub> + Z i </ "sub> is an even number." And "A X </ sub> + A Z </ sub> + Z j </ sub> is an even number." If you know one of the A's, you know the other two.

Then the question is how many groups A have no relation to each other, and the problem can be reduced to just counting the number of groups with Union Find.

from sys import setrecursionlimit


def find(parent, i):
    t = parent[i]
    if t < 0:
        return i
    t = find(parent, t)
    parent[i] = t
    return t


def unite(parent, i, j):
    i = find(parent, i)
    j = find(parent, j)
    if i == j:
        return
    parent[j] += parent[i]
    parent[i] = j


setrecursionlimit(10 ** 5)

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

parent = [-1] * N
for _ in range(M):
    X, Y, Z = map(int, input().split())
    unite(parent, X - 1, Y - 1)
print(len([x for x in parent if x < 0]))

ABC052D - Walk and Teleport

Just walk and teleport in order, and visit with the one with the least increase in fatigue. Easy.

N, A, B = map(int, input().split())
X = list(map(int, input().split()))

result = 0
for i in range(N - 1):
    result += min(A * (X[i + 1] - X[i]), B)
print(result)

ABC079D - Wall

For all numbers except -1 and 1, we just add the magical power needed to change it to 1, but there are cases where it requires less magical power to go through another number than to change it directly to 1. , Find the minimum magical power to change each number to 1 by the Worshall Floyd method.

def warshall_floyd(n, d):
    for i in range(n):
        for j in range(n):
            for k in range(n):
                d[j][k] = min(d[j][k], d[j][i] + d[i][k])


H, W = map(int, input().split())

N = 10
d = [None] * N
for i in range(N):
    d[i] = list(map(int, input().split()))
warshall_floyd(N, d)

m = [d[i][1] for i in range(N)]

result = 0
for _ in range(H):
    for i in map(int, input().split()):
        if i == -1:
            continue
        result += m[i]
print(result)

ABC085D - Katana Thrower

Only the sword with the maximum damage can be swung. No sword with less damage than this swinging damage is required. If the damage is thrown in descending order and the damage exceeds H before reaching the maximum damage to be swung. There is no need to shake. If there is not enough, shake it by that amount. If the sword to be shaken is in the sword to be thrown, if you throw it after shaking, the number of times will be the same, so there is no problem.

N, H = map(int, input().split())
a, b = zip(*(map(int, input().split()) for _ in range(N)))

a_max = max(a)                   #Maximum damage of shaking
b = [x for x in b if x > a_max]  #A sword whose throwing damage is lower than the maximum damage of swinging is meaningless to throw, so remove it
b.sort(reverse=True)

result = 0

#Throw swords in descending order of damage, and if you can defeat them before the sword runs out, that's it.
for x in b:
    result += 1
    H -= x
    if H <= 0:
        break

#If you can't defeat it just by throwing it, swing the sword with the maximum damage.
#If the sword with the maximum damage to swing is in the sword to be thrown, it means that it was thrown after swinging as much as necessary
if H > 0:
    result += (H + (a_max - 1)) // a_max

print(result)

Recommended Posts

AtCoder Beginners Contest Past Question Challenge 6
AtCoder Beginners Contest Past Question Challenge 4
AtCoder Beginners Contest Past Question Challenge 9
AtCoder Beginners Contest Past Question Challenge 7
AtCoder Beginners Contest Past Question Challenge 10
AtCoder Beginners Contest Past Question Challenge 5
AtCoder Grand Contest Past Question Challenge 2
AtCoder Grand Contest Past Question Challenge 1
AtCoder Past Question Review (12 / 6,7)
AtCoder Past Question Review (12/5)
Challenge AtCoder
AtCoder Beginner Contest 066 Review past questions
# 2 Python beginners challenge AtCoder! ABC085C --Otoshidama
AtCoder Beginner Contest 102 Review of past questions
AtCoder Beginner Contest 085 Review of past questions
AtCoder Beginner Contest 062 Review of past questions
AtCoder Beginner Contest 113 Review of past questions
AtCoder Beginner Contest 074 Review of past questions
AtCoder Beginner Contest 051 Review of past questions
AtCoder Beginner Contest 127 Review of past questions
AtCoder Beginner Contest 119 Review of past questions
AtCoder Beginner Contest 151 Review of past questions
AtCoder Beginner Contest 075 Review of past questions
AtCoder Beginner Contest 054 Review of past questions
AtCoder Beginner Contest 110 Review of past questions
AtCoder Beginner Contest 117 Review of past questions
AtCoder Beginner Contest 070 Review of past questions
AtCoder Beginner Contest 105 Review of past questions
AtCoder Beginner Contest 112 Review of past questions
AtCoder Beginner Contest 076 Review of past questions
AtCoder Beginner Contest 089 Review of past questions
AtCoder Beginner Contest 069 Review of past questions
AtCoder Beginner Contest 079 Review of past questions
AtCoder Beginner Contest 056 Review of past questions
AtCoder Beginner Contest 087 Review of past questions
AtCoder Beginner Contest 067 Review of past questions
AtCoder Beginner Contest 093 Review of past questions
AtCoder Beginner Contest 046 Review of past questions
AtCoder Beginner Contest 123 Review of past questions
AtCoder Beginner Contest 049 Review of past questions
AtCoder Beginner Contest 078 Review of past questions
AtCoder Beginner Contest 081 Review of past questions
AtCoder Beginner Contest 047 Review of past questions
AtCoder Beginner Contest 060 Review of past questions
AtCoder Beginner Contest 104 Review of past questions
AtCoder Beginner Contest 057 Review of past questions
AtCoder Beginner Contest 121 Review of past questions
AtCoder Beginner Contest 126 Review of past questions
AtCoder Beginner Contest 090 Review of past questions
AtCoder Beginner Contest 103 Review of past questions
AtCoder Beginner Contest 061 Review of past questions
AtCoder Beginner Contest 059 Review of past questions
AtCoder Beginner Contest 044 Review of past questions
AtCoder Beginner Contest 083 Review of past questions
AtCoder Beginner Contest 048 Review of past questions
AtCoder Beginner Contest 124 Review of past questions
AtCoder Beginner Contest 116 Review of past questions
AtCoder Beginner Contest 097 Review of past questions
AtCoder Beginner Contest 088 Review of past questions
AtCoder Beginner Contest 092 Review of past questions
AtCoder Beginner Contest 099 Review of past questions