AOJ ALDS1_1_A, ALDS1_2_A, ALDS1_2_B

備忘録

問題

ALDS1_1_A
http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_1_A&lang=ja

回答

import sys, os, math, bisect, itertools, collections, heapq, queue
# from scipy.sparse.csgraph import csgraph_from_dense, floyd_warshall
from decimal import Decimal
from collections import defaultdict, deque

sys.setrecursionlimit(10000000)

ii = lambda: int(sys.stdin.buffer.readline().rstrip())
il = lambda: list(map(int, sys.stdin.buffer.readline().split()))
fl = lambda: list(map(float, sys.stdin.buffer.readline().split()))
iln = lambda n: [int(sys.stdin.buffer.readline().rstrip()) for _ in range(n)]

iss = lambda: sys.stdin.buffer.readline().decode().rstrip()
sl = lambda: list(map(str, sys.stdin.buffer.readline().decode().split()))
isn = lambda n: [sys.stdin.buffer.readline().decode().rstrip() for _ in range(n)]

lcm = lambda x, y: (x * y) // math.gcd(x, y)

MOD = 10 ** 9 + 7
MAX = float('inf')


def insertion_sort(A, N):
    for i in range(N):
        v = A[i]
        j = i - 1
        while j >= 0 and A[j] > v:
            A[j + 1] = A[j]
            j -= 1
        A[j + 1] = v
        print(*A)


def main():
    if os.getenv("LOCAL"):
        sys.stdin = open("input.txt", "r")

    N = ii()
    A = il()
    insertion_sort(A, N)


if __name__ == '__main__':
    main()

---

問題

ALDS1_2_A
http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_2_A&lang=jp

回答

import sys, os, math, bisect, itertools, collections, heapq, queue
# from scipy.sparse.csgraph import csgraph_from_dense, floyd_warshall
from decimal import Decimal
from collections import defaultdict, deque

sys.setrecursionlimit(10000000)

ii = lambda: int(sys.stdin.buffer.readline().rstrip())
il = lambda: list(map(int, sys.stdin.buffer.readline().split()))
fl = lambda: list(map(float, sys.stdin.buffer.readline().split()))
iln = lambda n: [int(sys.stdin.buffer.readline().rstrip()) for _ in range(n)]

iss = lambda: sys.stdin.buffer.readline().decode().rstrip()
sl = lambda: list(map(str, sys.stdin.buffer.readline().decode().split()))
isn = lambda n: [sys.stdin.buffer.readline().decode().rstrip() for _ in range(n)]

lcm = lambda x, y: (x * y) // math.gcd(x, y)

MOD = 10 ** 9 + 7
MAX = float('inf')


def bubble_sort(A, N):
    flag = 1
    cnt = 0
    while flag:
        flag = 0
        for j in reversed(range(1, N)):
            if A[j] < A[j - 1]:
                A[j], A[j - 1] = A[j - 1], A[j]
                flag = 1
                cnt += 1
    return cnt


def main():
    if os.getenv("LOCAL"):
        sys.stdin = open("input.txt", "r")

    N = ii()
    A = il()
    cnt = bubble_sort(A, N)
    print(*A)
    print(cnt)


if __name__ == '__main__':
    main()

---

問題

ALDS1_2_B
http://judge.u-aizu.ac.jp/onlinejudge/description.jsp?id=ALDS1_2_B&lang=ja

回答

import sys, os, math, bisect, itertools, collections, heapq, queue
# from scipy.sparse.csgraph import csgraph_from_dense, floyd_warshall
from decimal import Decimal
from collections import defaultdict, deque

sys.setrecursionlimit(10000000)

ii = lambda: int(sys.stdin.buffer.readline().rstrip())
il = lambda: list(map(int, sys.stdin.buffer.readline().split()))
fl = lambda: list(map(float, sys.stdin.buffer.readline().split()))
iln = lambda n: [int(sys.stdin.buffer.readline().rstrip()) for _ in range(n)]

iss = lambda: sys.stdin.buffer.readline().decode().rstrip()
sl = lambda: list(map(str, sys.stdin.buffer.readline().decode().split()))
isn = lambda n: [sys.stdin.buffer.readline().decode().rstrip() for _ in range(n)]

lcm = lambda x, y: (x * y) // math.gcd(x, y)

MOD = 10 ** 9 + 7
MAX = float('inf')


def selection_sort(A, N):
    cnt = 0
    for i in range(N):
        minj = i
        for j in range(i, N):
            if A[j] < A[minj]:
                minj = j
        if i != minj:
            A[i], A[minj] = A[minj], A[i]
            cnt += 1
    return cnt


def main():
    if os.getenv("LOCAL"):
        sys.stdin = open("input.txt", "r")

    N = ii()
    A = il()
    cnt = selection_sort(A, N)
    print(*A)
    print(cnt)


if __name__ == '__main__':
    main()

考え方

螺旋本より、AOJのソート問題3問。
基本的には、愚直に指示通り実装を行う。
注意点として、問題で問われているソートの実行回数等を正しく算出すること。