Link List Simulation

const int N = 100010, M = N * 2;
int h[N], e[M], ne[M], w[M], idx;
void add(int a, int b, int c) { // add a->b wight=c
	e[idx] = b, w[idx] = c, ne[idx] = h[a], h[a] = idx ++;
}

This code can use for storage graph or tree.