diff options
Diffstat (limited to 'dsa/DSALib/Auxiliary/Calculator/StringSolver.cs')
| -rw-r--r-- | dsa/DSALib/Auxiliary/Calculator/StringSolver.cs | 183 |
1 files changed, 183 insertions, 0 deletions
diff --git a/dsa/DSALib/Auxiliary/Calculator/StringSolver.cs b/dsa/DSALib/Auxiliary/Calculator/StringSolver.cs new file mode 100644 index 0000000..45d6a54 --- /dev/null +++ b/dsa/DSALib/Auxiliary/Calculator/StringSolver.cs @@ -0,0 +1,183 @@ +using System; +using System.Collections.Generic; +using System.Linq; +using DSALibv.Auxiliary.Calculator; + +namespace DSALib.Auxiliary.Calculator +{ + /// <summary> + /// The StringSolver divides the calculation string into operations and SubStringSolvers if the string contains + /// parentheses + /// </summary> + public class StringSolver : ISolvable + { + private readonly List<object> arguments = new List<object>(); + private readonly string input; + + public StringSolver(string input) + { + this.input = input; + } + + public int Solve() + { + var workInput = "0+" + input.Replace(" ", string.Empty).ToLower(); + workInput = ExpandParentheses(workInput); + + // Create a List of the different parts of the calculation, e.g.:{"0", "+", "(5+6)", "d", "3"}. + AtomizeOperations(workInput); + + // traverse the List in order of Operation to Create the binary operation tree . + NestOperations(); + + // the List now contains only the top operation node, witch can be solved recursively, + return ((ISolvable) arguments.First()).Solve(); + } + + public override string ToString() + { + return "(0+" + input.Replace(" ", string.Empty).ToLower() + ")"; + } + + private static string + GetInner(ref string input) // extract the inner bracket an remove the section from the input string + { + var depth = 0; + for (var index = 1; index < input.Length; index++) + { + var c = input[index]; + switch (c) + { + case '(': + depth++; + break; + case ')': + if (depth == 0) + { + var split = input.Substring(1, index - 1); + input = input.Substring(index + 1); + return split.Equals(string.Empty) ? "0" : split; + } + else + { + depth--; + } + + break; + } + } + + throw new ArgumentException("Invalid brace sequence"); + } + + private static Ops GetOps(char c) + { + switch (c) + { + case 'd': + case 'w': + return Ops.Dice; + case '+': + return Ops.Add; + case '-': + return Ops.Subtract; + case '*': + return Ops.Multiply; + default: + return Ops.Multiply; + } + } + + private static string ExpandParentheses(string input) // insert * between Parentheses and digits + { + for (var i = 0; i < input.Length - 1; i++) + if (input[i + 1] == '(' && char.IsNumber(input[i])) + input = input.Insert(i + 1, "*"); + + for (var i = 1; i < input.Length; i++) + if (input[i - 1] == ')' && char.IsNumber(input[i])) + input = input.Insert(i, "*"); + + return input; + } + + private void AtomizeOperations(string workInput) + { + for (var index = 0; index < workInput.Length; index++) + { + var c = workInput[index]; + + if (char.IsNumber(c)) + { + // if char number, check if at end of string, else continue looping + if (index == workInput.Length - 1) + // if at end of string; add remaining number to arguments + arguments.Add(new Argument(workInput.Substring(0, index + 1))); + + continue; + } + + switch (c) + { + case ')': + throw new ArgumentException("Invalid brace sequence"); + case '(': + arguments.Add(new StringSolver(GetInner(ref workInput))); + index = -1; + break; + default: + if (index > 0) arguments.Add(new Argument(workInput.Substring(0, index))); + + arguments.Add(GetOps(c)); + workInput = workInput.Remove(0, index + 1); + index = -1; + break; + } + } + } + + private void NestOperations() + { + foreach (Ops currentOp in Enum.GetValues(typeof(Ops))) + // cycle through operators in operational order + for (var index = 0; index < arguments.Count; index++) + { + var arg = arguments[index]; + + if (arg.GetType() != typeof(Ops)) continue; + + // arg is of type Ops + var op = (Ops) arg; + + if (op != currentOp) continue; + + // arg describes the current operation + HandleSpecialFormatting(ref index, op); // Deal with special needs... + + // replace the previous current and next Element in the List with one Operation object + var temp = new Operator((ISolvable) arguments[index - 1], (ISolvable) arguments[index + 1], op); + arguments[index - 1] = temp; + arguments.RemoveRange(index, 2); + index--; + } + } + + private void HandleSpecialFormatting(ref int index, Ops op) + { + var arg1 = arguments[index - 1]; + if (arg1.GetType() == typeof(Ops)) + { + if (op == Ops.Dice) arguments.Insert(index++, new Argument("1")); // w6 -> 1w6 + + if (op == Ops.Subtract) arguments.Insert(index++, new Argument("0")); // +-3 -> +0-3 + } + + var arg2 = arguments[index + 1]; // 3+-5 -> 3+(0-5) + if (arg2.GetType() == typeof(Ops)) + { + arguments[index + 1] = new Operator(new Argument("0"), (ISolvable) arguments[index + 2], (Ops) arg2); + arguments.RemoveAt(index + 2); + } + } + } +}
\ No newline at end of file |