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class Solution {
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  public double soupServings(int n) {
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    if (n > 4800) return 1;
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    n = (int) Math.ceil(n * 1.0 / 25);
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    double dp[][] = new double[n + 1][n + 1];
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    return helper(n, n, dp);
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  }
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  double helper(int a, int b, double dp[][]) {
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    if (a <= 0 && b <= 0) return 0.5;
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    if (b <= 0) return 0;
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    if (a <= 0) return 1;
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    if (dp[a][b] > 0) return dp[a][b];
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    return dp[a][b] =
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        0.25
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            * (helper(a - 4, b, dp)
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                + helper(a - 3, b - 1, dp)
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                + helper(a - 2, b - 2, dp)
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                + helper(a - 1, b - 3, dp));
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  }
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}
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// Upvote please !!