// ---------- begin input macro ---------- // reference: https://qiita.com/tanakh/items/0ba42c7ca36cd29d0ac8 macro_rules! input { (source = $s:expr, $($r:tt)*) => { let mut iter = $s.split_whitespace(); input_inner!{iter, $($r)*} }; ($($r:tt)*) => { let s = { use std::io::Read; let mut s = String::new(); std::io::stdin().read_to_string(&mut s).unwrap(); s }; let mut iter = s.split_whitespace(); input_inner!{iter, $($r)*} }; } macro_rules! input_inner { ($iter:expr) => {}; ($iter:expr, ) => {}; ($iter:expr, $var:ident : $t:tt $($r:tt)*) => { let $var = read_value!($iter, $t); input_inner!{$iter $($r)*} }; } macro_rules! read_value { ($iter:expr, ( $($t:tt),* )) => { ( $(read_value!($iter, $t)),* ) }; ($iter:expr, [ $t:tt ; $len:expr ]) => { (0..$len).map(|_| read_value!($iter, $t)).collect::>() }; ($iter:expr, chars) => { read_value!($iter, String).chars().collect::>() }; ($iter:expr, bytes) => { read_value!($iter, String).bytes().collect::>() }; ($iter:expr, usize1) => { read_value!($iter, usize) - 1 }; ($iter:expr, $t:ty) => { $iter.next().unwrap().parse::<$t>().expect("Parse error") }; } // ---------- end input macro ---------- fn run() { input! { n: usize, e: [(usize1, usize1, u32); n - 1], } let mut g = vec![vec![]; n]; for (a, b, c) in e { g[a].push((b, c)); g[b].push((a, c)); } let mut topo = vec![0]; for i in 0..n { let v = topo[i]; for (u, _) in g[v].clone() { g[u].retain(|p| p.0 != v); topo.push(u); } } const MOD: u64 = 1_000_000_007; let mut ans = 0u64; for i in 0..30 { let mut dp = vec![0; n]; let mut cnt = 0; for &v in topo.iter().rev() { let mut c = 1; for &(u, w) in g[v].iter() { if w >> i & 1 == 1 { cnt += c * dp[u]; c += dp[u]; } } dp[v] = c; } ans += cnt << i; } ans %= MOD; println!("{}", ans); } fn main() { run(); }