CodeForces 348B Apple Tree

这题的解法有点神啊。。

参考题解

#include <cstdio>
#include <cstring>
#include <algorithm>
#include <vector>
using namespace std;

typedef long long LL;
const LL INF = (1LL << 60);

const int maxn = 200000 + 10;
int n;
LL val[maxn];
vector<int> G[maxn];

LL gcd(LL a, LL b) { return !b ? a : gcd(b, a % b); }
LL lcm(LL a, LL b) { return a / gcd(a, b) * b; }

LL L = INF, M = 1, sum;

void dfs(int u, int fa, LL d)
{
    M = lcm(M, d);
    if(d > sum || d < 0) { printf("%I64d
", sum); exit(0); }
    if(u > 1 && G[u].size() == 1) L = min(L, val[u] * d);
    for(int v : G[u]) if(v != fa)
        dfs(v, u, d * (G[u].size() - (u == 1 ? 0 : 1)));
}

int main()
{
    scanf("%d", &n);
    for(int i = 1; i <= n; i++) { scanf("%I64d", val + i); sum += val[i]; }
    for(int i = 1; i < n; i++)
    {
        int u, v; scanf("%d%d", &u, &v);
        G[u].push_back(v); G[v].push_back(u);
    }

    dfs(1, 0, 1);
    printf("%I64d
", sum - L / M * M);

    return 0;
}