Submission #1694265

---

Source Code Expand

#include <cstdio>
#include <algorithm>
int head[100001], next[199999], to[199999], len[199999], N, E, q[100001], fa[100001], fe[100001], size[100001], mxson[100001];
long long O;
int main()
{
	scanf("%d", &N);
	for (int i = 1, u, v, l; i < N; i++)
	{
		scanf("%d%d%d", &u, &v, &l);
		next[++E] = head[u], to[E] = v, len[E] = l, head[u] = E;
		next[++E] = head[v], to[E] = u, len[E] = l, head[v] = E;
	}
	int H = 0, T = 1, u;
	q[1] = 1;
	while (H < T)
		for (int e = head[u = q[++H]]; e; e = next[e])
			if (to[e] != fa[u])
			{
				fa[q[++T] = to[e]] = u;
				fe[to[e]] = e;
			}
	for (int i = 1; i <= N; i++)
		size[i] = 1;
	for (int i = N; i > 1; i--)
	{
		size[fa[q[i]]] += size[q[i]];
		mxson[fa[q[i]]] = std::max(mxson[fa[q[i]]], size[q[i]]);
	}
	for (int i = 2; i <= N; i++)
		O += (long long)std::min(size[i], N - size[i]) * len[fe[i]];
	O <<= 1;
	for (int i = 2; i <= N; i++)
		if (size[i] << 1 > N && mxson[i] << 1 < N)
		{
			int XA = 1000000000;
			for (int e = head[i]; e; e = next[e])
				XA = std::min(XA, len[e]);
			printf("%lld\n", O - XA);
			return 0;
		}
	for (int i = 2; i <= N; i++)
		if (size[i] << 1 == N)
		{
			printf("%lld\n", O - len[fe[i]]);
			return 0;
		}
	return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:7:17: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &N);
                 ^
./Main.cpp:10:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d", &u, &v, &l);
                              ^

Judge Result