求助，检查代码

inline void dfs2(int x, int fir) {
	ans += f[x];
	for (int i = head[x]; i; i = e[i].nxt) {
		if (e[i].to != fir) {
			if (f[e[i].to] * e[i].w != 1) f[e[i].to] = re(f[e[i].to], re(f[x], f[e[i].to] * e[i].w, 1) * e[i].w, 0);
			dfs2(e[i].to, x);
		}
	}
}

inline void dfs2(int x, int fir) {
	ans += f[x];
	for (int i = head[x]; i; i = e[i].nxt) {
		if (e[i].to == fir) continue;
		dfs2(e[i].to, x);
		if ( f[e[i].to] * e[i].w == 1) continue;
		f[e[i].to] = re(f[e[i].to], re(f[x], f[e[i].to] * e[i].w, 1) * e[i].w, 0);
	}
}