{"record":{"id":"09a56101ea16cf7a","repo":"TheAlgorithms/C-Sharp","slug":"the-alpha-parameter-s-value-should-be-in-0-5-1-0-range","errorCode":null,"errorMessage":"The alpha parameter's value should be in 0.5..1.0 range.","messagePattern":"The alpha parameter's value should be in 0\\.5\\.\\.1\\.0 range\\.","errorType":"exception","errorClass":"ArgumentException","httpStatus":null,"severity":"error","filePath":"DataStructures/ScapegoatTree/ScapegoatTree.cs","lineNumber":273,"sourceCode":"\n        while (path.TryPop(out var next))\n        {\n            if (depth > next.GetAlphaHeight(Alpha))\n            {\n                return path.TryPop(out var parent) ? (parent, next) : (null, next);\n            }\n\n            depth++;\n        }\n\n        throw new InvalidOperationException(\"Scapegoat node wasn't found. The tree should be unbalanced.\");\n    }\n\n    private static void CheckAlpha(double alpha)\n    {\n        if (alpha is < 0.5 or > 1.0)\n        {\n            throw new ArgumentException(\"The alpha parameter's value should be in 0.5..1.0 range.\", nameof(alpha));\n        }\n    }\n\n    private bool Remove(Node<TKey>? parent, Node<TKey>? node, TKey key)\n    {\n        if (node is null || parent is null)\n        {\n            return false;\n        }\n\n        var compareResult = node.Key.CompareTo(key);\n\n        if (compareResult > 0)\n        {\n            return Remove(node, node.Left, key);\n        }\n\n        if (compareResult < 0)","sourceCodeStart":255,"sourceCodeEnd":291,"githubUrl":"https://github.com/TheAlgorithms/C-Sharp/blob/96e2905cab7bc6b33ac0a34ee5bb82ddccbcbb6c/DataStructures/ScapegoatTree/ScapegoatTree.cs#L255-L291","documentation":"CheckAlpha validates the alpha weight-balance parameter of ScapegoatTree. Alpha must lie in [0.5, 1.0]; values below 0.5 would demand impossible balance and above 1.0 disable rebalancing checks. Invalid values passed to the constructor or Tune throw ArgumentException naming `alpha`.","triggerScenarios":"new ScapegoatTree<double>(alpha) or tree.Tune(alpha) with alpha < 0.5 or alpha > 1.0, including NaN comparisons failing the range pattern.","commonSituations":"Config-driven alpha read from app settings as a percentage (e.g. 75 instead of 0.75), inverted bounds like 1.5, or a misparsed decimal separator.","solutions":["Clamp or validate alpha to the 0.5..1.0 range before constructing/tuning.","If the value comes from config as a percentage, divide by 100 first.","Check for NaN/parse failures when alpha originates from user input."],"exampleFix":"// before\nvar tree = new ScapegoatTree<int>(75);\n// after\nvar alpha = 75 / 100.0;\nvar tree = new ScapegoatTree<int>(alpha);","handlingStrategy":"validation","validationCode":"if (double.IsNaN(alpha) || alpha < 0.5 || alpha > 1.0) throw new ArgumentOutOfRangeException(nameof(alpha), alpha, \"alpha must be in [0.5, 1.0]\");","typeGuard":"static bool IsValidAlpha(double alpha) => !double.IsNaN(alpha) && alpha >= 0.5 && alpha <= 1.0;","tryCatchPattern":"try { tree.Tune(alpha); } catch (ArgumentException ex) { logger.LogWarning(ex, \"Invalid alpha, keeping previous value\"); }","preventionTips":["Convert percentages to fractions before passing alpha.","Clamp config-sourced alpha into [0.5, 1.0].","Watch for decimal-separator parsing issues in localized configs."],"tags":["argument-validation","configuration","trees"],"backgroundTag":"value-out-of-range","analyzedSha":"96e2905cab7bc6b33ac0a34ee5bb82ddccbcbb6c","analyzedAt":"2026-09-13T17:04:01.438Z","contentChangedAt":"2026-09-13T17:04:01.438Z","schemaVersion":2},"datasetVersion":"2026-09-16T04:17:20.429Z"}