public class ExactTreeEasy { public int[] getTree(int n, int m) { int[] ret = new int[(n-1)*2]; int p = 0; ret[p++] = 0; ret[p++] = 1; ret[p++] = 1; ret[p++] = 2; int nodeIndex = 2; for(int i = 1; i <= m-2; i++) { ret[p++] = 1; ret[p++] = ++nodeIndex; } while(nodeIndex < n-1) { ret[p++] = nodeIndex; ret[p++] = ++nodeIndex; } return ret; } }