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December 2, 2018 07:12
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#include <bits/stdc++.h> | |
using namespace std; | |
using ll = long long; | |
struct UnionFind { | |
vector<ll> sz, par, cost; | |
UnionFind(ll n):sz(n, 1), par(n), cost(n, 0) { | |
iota(par.begin(), par.end(), 0); | |
} | |
ll find(ll x) { | |
if(par[x] == x) return x; | |
ll r = find(par[x]); | |
if(r != par[x]) cost[x] += cost[par[x]]; | |
return par[x] = r; | |
} | |
void unite(ll x, ll y, ll w) { | |
x = find(x), y = find(y); | |
if(sz[x] < sz[y]) swap(x, y); | |
cost[x] += sz[y]*w; | |
cost[y] += sz[x]*w - cost[x]; | |
sz[x] += sz[y]; | |
par[y] = x; | |
} | |
ll get(ll x) { | |
ll r = find(x); | |
return cost[x] + (r == x ? 0 : cost[r]); | |
} | |
}; | |
using edge = tuple<ll, ll, ll>; | |
int main() { | |
ll N; | |
while(scanf("%lld", &N) != EOF) { | |
vector<edge> es; | |
for(ll i = 1; i < N; ++i) { | |
ll a, b, c; | |
scanf("%lld %lld %lld", &a, &b, &c); | |
--a, --b; | |
es.emplace_back(c, a, b); | |
} | |
sort(es.rbegin(), es.rend()); | |
UnionFind uf(N); | |
for(edge e : es) { | |
ll a, b, c; | |
tie(c, a, b) = e; | |
uf.unite(a, b, c); | |
} | |
ll ans = 0; | |
for(ll i = 0; i < N; ++i) ans = max(ans, uf.get(i)); | |
printf("%lld\n", ans); | |
} | |
return 0; | |
} |
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