The mentor recommendation is "Be sure that no exceptions occur in the getNumbers method for any input data."
I tried many ways but could not pass the verification. Pl help
package com.codegym.task.task20.task2025;
import java.util.ArrayList;
import java.util.Collections;
import java.util.List;
/*
Number algorithms
*/
public class Solution {
private static int N;
private static int[] digitsMultiSet;
private static int[] testMultiSet;
private static List<Long> results;
private static long maxPow;
private static long minPow;
private static long[][] pows;
private static void genPows(int N) {
try {
pows = new long[10][N + 1];
for (int i = 0; i < pows.length; i++) {
long p = 1;
for (int j = 0; j < pows[i].length; j++) {
pows[i][j] = p;
p *= i;
}
}
}catch (Exception e){
e.printStackTrace();
}
}
private static boolean check(long pow) {
if (pow >= maxPow) return false;
if (pow < minPow) return false;
for (int i = 0; i < 10; i++) {
testMultiSet[i] = 0;
}
while (pow > 0) {
int i = (int) (pow % 10);
testMultiSet[i]++;
if (testMultiSet[i] > digitsMultiSet[i]) return false;
pow = pow / 10;
}
for (int i = 0; i < 10; i++) {
if (testMultiSet[i] != digitsMultiSet[i]) return false;
}
return true;
}
private static void search(int digit, int unused, long pow) {
if (pow >= maxPow) return;
if (digit == -1) {
if (check(pow)) results.add(pow);
return;
}
if (digit == 0) {
digitsMultiSet[digit] = unused;
search(digit - 1, 0, pow + unused * pows[digit][N]);
} else {
// Check if we can generate more than minimum
if (pow + unused * pows[digit][N] < minPow) return;
long p = pow;
for (int i = 0; i <= unused; i++) {
digitsMultiSet[digit] = i;
search(digit - 1, unused - i, p);
if (i != unused) {
p += pows[digit][N];
// Check maximum and break the loop - doesn't help
// if (p >= maxPow) break;
}
}
}
}
public static Long[] getNumbers(long maxN) {
long rdNumber = maxN;
long temp = maxN;
long count = 0;
while(temp != 0)
{
temp /= 10;
++count;
}
maxN = count;
genPows((int) maxN);
results = new ArrayList<>();
digitsMultiSet = new int[10];
testMultiSet = new int[10];
for (N = 1; N <= maxN; N++) {
minPow = (long) Math.pow(10, N - 1);
maxPow = (long) Math.pow(10, N);
search(9, N, 0);
}
Collections.sort(results);
Long[] result = new Long[results.size()];
for (int i = 0; i < results.size(); i++){
result[i] = results.get(i);
}
return result;
}
public static void main(String[] args) {
long start = System.currentTimeMillis();
Long[] result = getNumbers(9223372036854775807L);
long finish = System.currentTimeMillis();
System.out.println("Time consumed: " + (finish - start) + " ms");
for (int i = 0; i < result.length; i++){
System.out.println(result[i]);
}
}
}