結果

問題 No.19 ステージの選択
ユーザー zundamo-tizundamo-ti
提出日時 2021-01-08 06:48:09
言語 Python3
(3.11.6 + numpy 1.26.0 + scipy 1.11.3)
結果
AC  
実行時間 17 ms / 5,000 ms
コード長 2,074 bytes
コンパイル時間 959 ms
コンパイル使用メモリ 11,216 KB
実行使用メモリ 8,252 KB
最終ジャッジ日時 2023-08-09 11:37:20
合計ジャッジ時間 2,795 ms
ジャッジサーバーID
(参考情報)
judge13 / judge14
このコードへのチャレンジ(β)

テストケース

テストケース表示
入力 結果 実行時間
実行使用メモリ
testcase_00 AC 16 ms
8,184 KB
testcase_01 AC 16 ms
8,132 KB
testcase_02 AC 16 ms
8,140 KB
testcase_03 AC 17 ms
8,200 KB
testcase_04 AC 16 ms
8,044 KB
testcase_05 AC 17 ms
8,048 KB
testcase_06 AC 17 ms
8,128 KB
testcase_07 AC 17 ms
8,124 KB
testcase_08 AC 17 ms
8,108 KB
testcase_09 AC 16 ms
8,072 KB
testcase_10 AC 16 ms
8,076 KB
testcase_11 AC 17 ms
8,104 KB
testcase_12 AC 16 ms
8,076 KB
testcase_13 AC 16 ms
8,048 KB
testcase_14 AC 16 ms
8,252 KB
testcase_15 AC 16 ms
8,064 KB
testcase_16 AC 17 ms
8,136 KB
testcase_17 AC 16 ms
8,052 KB
testcase_18 AC 16 ms
8,168 KB
testcase_19 AC 16 ms
8,180 KB
testcase_20 AC 16 ms
8,068 KB
testcase_21 AC 16 ms
8,068 KB
testcase_22 AC 16 ms
8,168 KB
testcase_23 AC 16 ms
8,040 KB
権限があれば一括ダウンロードができます

ソースコード

diff #

import sys
sys.setrecursionlimit(10**9)
readline = sys.stdin.readline

def dfs(x, G, visited, log):
    visited[x] = True
    for y in G[x]:
        if visited[y]:
            continue
        dfs(y, G, visited, log)
    log.append(x)

def dp(i, DAG, visited, diff_of_I, memo):
    visited[i] = True
    memo[i] = diff_of_I[i]
    sum_diff = 0
    for j in DAG[i]:
        sum_diff += diff_of_I[j]
        dp(j, DAG, visited, diff_of_I, memo)
        memo[i] += memo[j]
    memo[i] -= sum_diff / 2

def main():
    N = int(readline())
    fr = [[] for _ in range(N)]
    to = [[] for _ in range(N)]
    difficulty = [0]*N
    for x in range(N):
        d, y = map(int, readline().split())
        y -= 1
        fr[x].append(y)
        to[y].append(x)
        difficulty[x] = d

    visited = [False]*N
    log = []
    for x in range(N):
        if visited[x]:
            continue
        dfs(x, to, visited, log)
    log.reverse()

    visited = [False]*N
    groups = []
    for x in log:
        if visited[x]:
            continue
        group = []
        dfs(x, fr, visited, group)
        groups.append(group)

    I = len(groups)
    V_to_I = [-1]*N
    diff_of_I = [-1]*I
    for i, group in enumerate(groups):
        min_diff = 1000
        sum_diff = 0
        for x in group:
            V_to_I[x] = i
            min_diff = min(min_diff, difficulty[x])
            sum_diff += difficulty[x]
        diff_of_I[i] = (min_diff + sum_diff) / 2

    DAG = [[] for _ in range(I)]
    for x in range(N):
        i = V_to_I[x]
        for y in to[x]:
            j = V_to_I[y]
            if i != j:
                DAG[i].append(j)

    visited = [False]*I
    components = []
    for i in range(I):
        if visited[i]:
            continue
        component = []
        dfs(i, DAG, visited, component)
        components.append(component)

    ans = 0
    memo = [0]*I
    for component in components:
        top = component.pop()
        dp(top, DAG, visited, diff_of_I, memo)
        ans += memo[top]
    print(ans)

if __name__ == "__main__":
    main()

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