Make Array Strictly Increasing LeetCode solution in Java

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class Solution {
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  public int makeArrayIncreasing(int[] A, int[] B) { // A = arr1, B = arr2
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    TreeSet<Integer> set = new TreeSet<>(Arrays.stream(B).boxed().toList());
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    int[] dp = new int[B.length + 1];
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    dp[0] = -1;
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    int INF = (int) 2e9;
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    for (int i = 0; i < A.length; i++) {
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      for (int j = B.length; j >= 0; j--) {
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        int a = A[i] > dp[j] ? A[i] : INF; // option A - don't swap
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        Integer b = set.higher(j == 0 ? INF : dp[j - 1]); // option B - swap
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        dp[j] = Math.min(a, b == null ? INF : b); // take the min of A and B
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      }
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    }
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    for (int i = 0; i <= B.length; i++)
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      if (dp[i] != INF) {
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        return i;
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      }
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    return -1;
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  }
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}