結果

問題 No.1300 Sum of Inversions
ユーザー tamato
提出日時 2020-11-27 21:52:35
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 609 ms / 2,000 ms
コード長 2,079 bytes
コンパイル時間 466 ms
コンパイル使用メモリ 82,356 KB
実行使用メモリ 125,496 KB
最終ジャッジ日時 2024-07-26 12:22:19
合計ジャッジ時間 17,058 ms
ジャッジサーバーID
（参考情報） 		judge4 / judge5
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ファイルパターン 結果
sample AC * 3
other AC * 34
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 # 

mod = 998244353
eps = 10**-9


def main():
    import sys
    input = sys.stdin.readline

    class Bit:
        def __init__(self, n):
            self.size = n
            self.tree = [0] * (n + 1)

        def sum(self, i):
            s = 0
            while i > 0:
                s += self.tree[i]
                i -= i & -i
            return s

        def add(self, i, x):
            while i <= self.size:
                self.tree[i] += x
                i += i & -i

        def lower_bound(self, w):
            if w <= 0:
                return 0
            x = 0
            k = 1 << (self.size.bit_length() - 1)
            while k:
                if x + k <= self.size and self.tree[x + k] < w:
                    w -= self.tree[x + k]
                    x += k
                k >>= 1
            return x + 1

    N = int(input())
    A = list(map(int, input().split()))
    A = [(a, i+1) for i, a in enumerate(A)]

    bit_val = Bit(N)
    bit_num = Bit(N)
    A.sort(key=lambda x: x[0], reverse=True)
    prev = -1
    L_val = [0] * (N+1)
    L_num = [0] * (N+1)
    cnt = 0
    for a, i in A:
        if a == prev:
            cnt += 1
        else:
            cnt = 0
            prev = a
        L_val[i] = bit_val.sum(i) - a * cnt
        L_num[i] = bit_num.sum(i) - cnt
        bit_val.add(i, a)
        bit_num.add(i, 1)

    bit_val = Bit(N)
    bit_num = Bit(N)
    A.reverse()
    prev = -1
    R_val = [0] * (N + 1)
    R_num = [0] * (N + 1)
    cnt = 0
    S_val = 0
    S_num = 0
    for a, i in A:
        if a == prev:
            cnt += 1
        else:
            cnt = 0
            prev = a
        R_val[i] = S_val - bit_val.sum(i) - a * cnt
        R_num[i] = S_num - bit_num.sum(i) - cnt
        bit_val.add(i, a)
        bit_num.add(i, 1)
        S_val += a
        S_num += 1

    ans = 0
    for a, i in A:
        ans = (ans + ((a * L_num[i])%mod * R_num[i])%mod)%mod
        ans = (ans + (L_val[i] * R_num[i])%mod)%mod
        ans = (ans + (R_val[i] * L_num[i])%mod)%mod
    print(ans)


if __name__ == '__main__':
    main()
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