Delivering Boxes from Storage to Ports LeetCode solution in Java

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class Solution {
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  public int boxDelivering(int[][] boxes, int portsCount, int maxBoxes, int maxWeight) {
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    int[] diffCity = new int[boxes.length + 1];
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    int[] weights = new int[boxes.length + 1];
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    for (int i = 0; i < boxes.length; i++) {
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      diffCity[i + 1] = diffCity[i] + ((i != 0 && boxes[i][0] == boxes[i - 1][0]) ? 0 : 1);
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      weights[i + 1] = weights[i] + boxes[i][1];
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    }
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    int[] dp = new int[boxes.length + 1];
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    Arrays.fill(dp, Integer.MAX_VALUE);
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    dp[0] = 0;
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    diffCity[0] = 1;
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    for (int i = 1; i <= boxes.length; i++) { // offset by 1 since our above logic reaches dp[-1]
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      for (int j = i - 1; j >= 0; j--) {
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        int dC =
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            diffCity[i]
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                - diffCity[j + 1]; // computes # of different cities from i to j. (add 1 to j is
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        // necessary here)
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        int w = weights[i] - weights[j];
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        int b = i - j;
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        if (b <= maxBoxes && w <= maxWeight) {
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          dp[i] = Math.min(dp[i], 2 + dC + dp[j]);
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        }
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      }
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    }
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    return dp[boxes.length];
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  }
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}