Longest Cycle in a Graph LeetCode solution in Java

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class Solution {
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  public int longestCycle(int[] edges) {
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    int[] map = new int[edges.length];
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    int result = -1;
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    for (int i = 0; i < edges.length; i++) result = Math.max(result, helper(i, 1, edges, map));
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    return result;
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  }
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  int helper(int index, int total, int[] edges, int[] map) {
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    if (index == -1 || map[index] == -1) return -1;
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    if (map[index] != 0) return total - map[index];
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    map[index] = total;
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    int result = helper(edges[index], total + 1, edges, map);
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    map[index] = -1;
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    return result;
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  }
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}