結果

問題 No.2377 SUM AND XOR on Tree
コンテスト
ユーザー lam6er
提出日時 2025-03-20 20:58:46
言語 PyPy3
(7.3.15)
結果
AC  
実行時間 1,350 ms / 4,000 ms
コード長 2,499 bytes
コンパイル時間 438 ms
コンパイル使用メモリ 82,172 KB
実行使用メモリ 202,844 KB
最終ジャッジ日時 2025-03-20 21:00:09
合計ジャッジ時間 23,112 ms
ジャッジサーバーID
（参考情報） 		judge1 / judge4
このコードへのチャレンジ
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ファイルパターン 結果
sample AC * 2
other AC * 33
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

def main():
    import sys
    input = sys.stdin.read
    data = input().split()
    idx = 0
    
    n = int(data[idx])
    idx += 1
    
    edges = [[] for _ in range(n+1)]
    for _ in range(n-1):
        u = int(data[idx])
        v = int(data[idx+1])
        edges[u].append(v)
        edges[v].append(u)
        idx += 2
    
    A = list(map(int, data[idx:idx+n]))
    idx += n
    
    # Build the tree structure with parent pointers and children list
    root = 1
    parent = [0] * (n + 1)
    children = [[] for _ in range(n + 1)]
    stack = [(root, 0)]
    while stack:
        u, p = stack.pop()
        parent[u] = p
        for v in edges[u]:
            if v != p:
                children[u].append(v)
                stack.append((v, u))
    
    total_ans = 0
    
    for b in range(30):
        # Compute a[u] for each node u (bit b)
        a = [0] * (n + 1)
        sum_xor = 0
        for u in range(1, n+1):
            au = (A[u-1] >> b) & 1
            a[u] = au
            sum_xor ^= au
        
        dp0 = [0] * (n + 1)
        dp1 = [0] * (n + 1)
        
        # Iterative post-order traversal
        stack = [(root, False)]
        while stack:
            u, visited = stack.pop()
            if not visited:
                stack.append((u, True))
                for v in reversed(children[u]):
                    stack.append((v, False))
            else:
                # Initialize with node u's a value
                if a[u] == 0:
                    curr0, curr1 = 1, 0
                else:
                    curr0, curr1 = 0, 1
                
                for v in children[u]:
                    v0 = dp0[v]
                    v1 = dp1[v]
                    
                    # Disconnect: curr * v1
                    new0 = (curr0 * v1) % MOD
                    new1 = (curr1 * v1) % MOD
                    
                    # Connect: curr * v0 and curr * v1, for both curr0 and curr1
                    con0 = (curr0 * v0 + curr1 * v1) % MOD
                    con1 = (curr0 * v1 + curr1 * v0) % MOD
                    
                    new0 = (new0 + con0) % MOD
                    new1 = (new1 + con1) % MOD
                    
                    curr0, curr1 = new0, new1
                
                dp0[u], dp1[u] = curr0, curr1
        
        ways = dp1[root]
        total_ans = (total_ans + (ways << b)) % MOD
    
    print(total_ans % MOD)

if __name__ == "__main__":
    main()
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