Minimum Path Sum LeetCode solution in Java

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class Solution {
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  public int minPathSum(int[][] grid) {
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    int m = grid.length;
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    int n = grid[0].length;
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    int[] dp = new int[n];
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    dp[0] = grid[0][0];
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    for (int i = 1; i < n; i++) {
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      dp[i] = dp[i - 1] + grid[0][i];
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    }
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    for (int i = 1; i < m; i++) {
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      for (int j = 0; j < n; j++) {
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        if (j == 0) dp[j] += grid[i][j];
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        else dp[j] = Math.min(dp[j], dp[j - 1]) + grid[i][j];
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      }
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    }
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    return dp[n - 1];
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  }
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}