本文实例分析了C#实现的24点游戏。分享给大家供大家参考。具体如下：

1. 24点游戏规则及算法

规则：给出4个自然数，找出能够求出24的四则运算式，要求数字不能重复使用

分析：

本算法是一种暴力求解法：

给出任意两个数字，可以进行6种四则运算，求出最多6个值。以数字a和b为例，有：

加（a+b）、减（a-b）、被减（b-a）、乘以（a*b）、除以(a/b)和除(b/a)

abcd共计四个数，如果顺序固定，则有5种计算顺序（★代表上面6种四则运算中的一种）：

((a★b)★c)★d、(a★b)★(c★d)、(a★(b★c))★d、a★((b★c)★d)、a★(b★(c★d))

给出的四个数字，n1n2n3n4，有4*3*2=24种全排列的方法

2. 相关函数

/// <summary> /// 判断abcd四个数进行任意四则运算后能不能得出24，每个数字只能用一次 /// </summary> /// <param name="a">数字a</param> /// <param name="b">数字b</param> /// <param name="c">数字c</param> /// <param name="d">数字d</param> /// <param name="expression"></param> /// <returns></returns> private static bool Try24(int a, int b, int c, int d, ref string expression) { //a字头 if (TryEach(a, b, c, d, ref expression)) return true; if (TryEach(a, b, d, c, ref expression)) return true; if (TryEach(a, c, b, d, ref expression)) return true; if (TryEach(a, c, d, b, ref expression)) return true; if (TryEach(a, d, b, c, ref expression)) return true; if (TryEach(a, d, c, b, ref expression)) return true; //b字头 if (TryEach(b, a, c, d, ref expression)) return true; if (TryEach(b, a, d, c, ref expression)) return true; if (TryEach(b, c, a, d, ref expression)) return true; if (TryEach(b, c, d, a, ref expression)) return true; if (TryEach(b, d, a, c, ref expression)) return true; if (TryEach(b, d, c, a, ref expression)) return true; //c字头 if (TryEach(c, a, b, d, ref expression)) return true; if (TryEach(c, a, d, b, ref expression)) return true; if (TryEach(c, b, a, c, ref expression)) return true; if (TryEach(c, b, c, a, ref expression)) return true; if (TryEach(c, d, a, b, ref expression)) return true; if (TryEach(c, d, b, a, ref expression)) return true; //d字头 if (TryEach(d, a, b, c, ref expression)) return true; if (TryEach(d, a, c, b, ref expression)) return true; if (TryEach(d, b, a, c, ref expression)) return true; if (TryEach(d, b, c, a, ref expression)) return true; if (TryEach(d, c, a, b, ref expression)) return true; if (TryEach(d, c, b, a, ref expression)) return true; return false; } /// <summary> /// 判断指定顺序的四个数abcd进行任意四则运算后能不能得出24，每个数字只能用一次 /// </summary> /// <param name="a">数字1</param> /// <param name="b">数字2</param> /// <param name="c">数字3</param> /// <param name="d">数字4</param> /// <param name="expression"></param> /// <returns></returns> private static bool TryEach(int a, int b, int c, int d, ref string expression) { expression = ""; //两个数可以做6种运算：加、减、被减、乘以、除以、除 //四个数共可以进行6*6*6=216种不同次序的四则运算 //初始化数组 for (int i = 0; i < 6 * 6 * 6; i++) { //a与b间的运算符：i / 36 //b与c间的运算符：i % 36 / 6 //c与d间的运算符：i % 6 //1.运算顺序：a和b，再和c，再和d { string expression1 = "", expression2 = ""; int temp1 = ResultOf(a, b, i / 36, ref expression1); int temp2 = ResultOf(temp1, c, i % 36 / 6, ref expression2, expression1); int result = ResultOf(temp2, d, i % 6, ref expression, expression2); if (result == 24) return true; } //2.运算顺序：a和b，c和d，前面部分和后面部分 { string expression1 = "", expression2 = ""; int temp1 = ResultOf(a, b, i / 36, ref expression1); int temp2 = ResultOf(c, d, i % 6, ref expression2); int result = ResultOf(temp1, temp2, i % 36 / 6, ref expression, expression1, expression2); if (result == 24) return true; } //3.运算顺序：b和c运算，再与a运算，再与d运算 { string expression1 = "", expression2 = ""; int temp1 = ResultOf(b, c, i % 36 / 6, ref expression1); int temp2 = ResultOf(a, temp1, i / 36, ref expression2, "", expression1); int result = ResultOf(temp2, d, i % 6, ref expression, expression2); if (result == 24) return true; } //4.运算顺序：b和c运算，再与d运算，再与a运算 { string expression1 = "", expression2 = ""; int temp1 = ResultOf(b, c, i % 36 / 6, ref expression1); int temp2 = ResultOf(temp1, d, i % 6, ref expression2, expression1); int result = ResultOf(a, temp2, i / 36, ref expression, "", expression2); if (result == 24) return true; } //5.运算顺序：c和d运算，再和b运算，再和a运算 { string expression1 = "", expression2 = ""; int temp1 = ResultOf(c, d, i % 6, ref expression1); int temp2 = ResultOf(b, temp1, i % 36 / 6, ref expression2, "", expression1); int result = ResultOf(a, temp2, i / 36, ref expression, "", expression2); if (result == 24) return true; } } expression = "Abandoned"; return false; } /// <summary> /// 求两数进行某一四则运算后的结果 /// </summary> /// <param name="x">数字1</param> /// <param name="y">数字2</param> /// <param name="method">（0-5分别代表：加、减、被减、乘以、除以、除）</param> /// <param name="expression">返回的表达式</param> /// <param name="expressionLeft">数字1表达式</param> /// <param name="expressionRight">数字2表达式</param> /// <returns></returns> private static int ResultOf(int x, int y, int method, ref string expression, string expressionLeft = "", string expressionRight = "") { //左右表达式之前被判定为无效则不计算，除数为0时不计算 if (expressionLeft == "Abandoned" || expressionRight == "Abandoned" || (x == 0 && method == 5) || (y == 0 && method == 4)) { expression = "Abandoned"; return -1; } int result = 0; switch (method) { case 0: { //加 result = x + y; expression = string.Format("{0}+{1}", expressionLeft == "" ? x.ToString() : expressionLeft, expressionRight == "" ? y.ToString() : expressionRight); } break; case 1: { //减 result = x - y; expression = string.Format("{0}-{1}", expressionLeft == "" ? x.ToString() : expressionLeft, expressionRight == "" ? y.ToString() : expressionRight); } break; case 2: { //被减 result = y - x; expression = string.Format("{1}-{0}", expressionLeft == "" ? x.ToString() : expressionLeft, expressionRight == "" ? y.ToString() : expressionRight); } break; case 3: { //乘以 result = x * y; expression = string.Format("({0})*({1})", expressionLeft == "" ? x.ToString() : expressionLeft, expressionRight == "" ? y.ToString() : expressionRight); } break; case 4: { //除以 if (x % y == 0) { result = x / y; expression = string.Format("({0})/({1})", expressionLeft == "" ? x.ToString() : expressionLeft, expressionRight == "" ? y.ToString() : expressionRight); } else { expression = "Abandoned"; } } break; case 5: { //除 if (y % x == 0) { result = y / x; expression = string.Format("({1})/({0})", expressionLeft == "" ? x.ToString() : expressionLeft, expressionRight == "" ? y.ToString() : expressionRight); } else { expression = "Abandoned"; } } break; } //运算不合法，则返回-1，表达式为Abandoned， if (expression == "Abandoned") { return -1; } return result; }

3. Main函数调用

static void Main(string[] args) { string s = ""; bool try24; try24 = Try24(1, 2, 3, 4, ref s); Console.WriteLine("1,2,3,4: " + s); try24 = Try24(1, 3, 5, 7, ref s); Console.WriteLine("1,3,5,7: " + s); try24 = Try24(2, 3, 6, 4, ref s); Console.WriteLine("2,3,6,4: " + s); try24 = Try24(5, 7, 9, 4, ref s); Console.WriteLine("5,7,9,4: " + s); try24 = Try24(6, 3, 4, 5, ref s); Console.WriteLine("6,3,4,5: " + s); try24 = Try24(9, 5, 2, 7, ref s); Console.WriteLine("9,5,2,7: " + s); try24 = Try24(4, 9, 8, 3, ref s); Console.WriteLine("4,9,8,3: " + s); try24 = Try24(4, 9, 8, 2, ref s); Console.WriteLine("4,9,8,2: " + s); try24 = Try24(10, 10, 10, 10, ref s); Console.WriteLine("10,10,10,10: " + s); Console.ReadLine(); }

4. 程序运行结果：

希望本文所述对大家的C#程序设计有所帮助。