update

Author: yangrubing

swordForOffer/src/main/java/problem45/LastNumberInCircle.java

@@ -1,16 +1,31 @@
 package problem45;
 
-import java.util.LinkedList;
+import java.util.ArrayList;
 
-/**0,1,2,.....,n-1这n个数字排成一个圆圈，从数字0开始每次删除圆圈内的第m个数字，求最后剩下的那个数字。
+/**
+ * 0,1,2,.....,n-1这n个数字排成一个圆圈，从数字0开始每次删除圆圈内的第m个数字，求最后剩下的那个数字。
  * Created by bjyangrubing on 2016/8/25.
  */
-public class LastNumberInCircle
-{
-	public int LastRemaining_Solution(int n, int m)
-	{
-        LinkedList list = new LinkedList();
-        list.last
-	}
+public class LastNumberInCircle {
+    public int LastRemaining_Solution(int n, int m) {
+        if (n < 1 || m < 1)
+            return -1;
+        ArrayList<Integer> list = new ArrayList<Integer>();
+        for (int i = 0; i < n; i++) {
+            list.add(i);
+        }
+
+        int begin = 0;
+        int removeIndex = (m - 1) % n;
+
+        while (list.size() > 1) {
+            list.remove((int) removeIndex);
+            begin = removeIndex % list.size();
+            removeIndex = (begin + m - 1) % list.size();
+        }
+        return list.get(0);
+
+    }
+
 
 }

swordForOffer/src/main/java/problem46/Accumulate.java

@@ -0,0 +1,17 @@
+package problem46;
+
+/**求1+2+3+...+n，要求不能使用乘除法、for、while、if、else、switch、case等关键字及条件判断语句（A?B:C）。
+ * Created by bjyangrubing on 2016/8/26.
+ */
+public class Accumulate
+{
+	/**递归*/
+	public int Sum_Solution(int n)
+	{
+		if (n == 1 || n == 0)
+			return n;
+
+		return n + Sum_Solution(n - 1);
+	}
+
+}

swordForOffer/src/main/java/problem47/AddTwoNumber.java

@@ -0,0 +1,26 @@
+package problem47;
+
+/**写一个函数，求两个整数之和，要求在函数体内不得使用+、-、*、/四则运算符号。
+ * Created by bjyangrubing on 2016/8/26.
+ */
+public class AddTwoNumber
+{
+	public int Add(int num1, int num2)
+	{
+		int sum, carry;
+
+		do
+		{
+			//先做异或,相当于各位相加不进位
+			sum = (num1 ^ num2);
+			//相当于进位
+			carry = (num1 & num2) << 1;
+
+			num1 = sum;
+			num2 = carry;
+		}
+		while (num2 != 0);
+
+		return num1;
+	}
+}

swordForOffer/src/main/java/problem48/FinalClass.java

@@ -0,0 +1,11 @@
+package problem48;
+
+/**不能被继承的类
+ * Created by bjyangrubing on 2016/8/26.
+ */
+public final class FinalClass
+{
+	private FinalClass()
+	{
+	}
+}

swordForOffer/src/main/java/problem49/StrToInt.java

@@ -0,0 +1,45 @@
+package problem49;
+
+/**
+ * 将一个字符串转换成一个整数，要求不能使用字符串转换整数的库函数。 数值为0或者字符串不是一个合法的数值则返回0
+ * Created by bjyangrubing on 2016/8/26.
+ */
+public class StrToInt
+{
+
+	public int strToInt(String str)
+	{
+		if (str == null || str.length() <= 0)
+			return 0;
+		char[] array = str.toCharArray();
+		boolean positive = true;
+		int beginIndex = 0;
+		if (array[0] == '-')
+		{
+			positive = false;
+			beginIndex += 1;
+		}
+		else if (array[0] == '+')
+		{
+			beginIndex += 1;
+		}
+		else if (!Character.isDigit(array[0]))
+		{
+			return 0;
+		}
+		int result = 0;
+		for (int i = beginIndex; i < array.length; i++)
+		{
+			if (!Character.isDigit(array[i]))
+			{
+				return 0;
+			}
+			result *= 10;
+			result -= (array[i] - '0');
+		}
+
+		return positive ? -result : result;
+
+	}
+
+}

swordForOffer/src/test/java/problem45/LastNumberInCircleTest.java

@@ -0,0 +1,20 @@
+package problem45;
+
+import junit.framework.Assert;
+import org.junit.Test;
+
+/**
+ * Created by bjyangrubing on 2016/8/26.
+ */
+public class LastNumberInCircleTest
+{
+
+	@Test
+	public void test()
+	{
+		LastNumberInCircle l = new LastNumberInCircle();
+
+		Assert.assertEquals(3, l.LastRemaining_Solution(5, 3));
+
+	}
+}

swordForOffer/src/test/java/problem46/AccumulateTest.java

@@ -0,0 +1,20 @@
+package problem46;
+
+import junit.framework.Assert;
+import org.junit.Test;
+
+/**
+ * Created by bjyangrubing on 2016/8/26.
+ */
+public class AccumulateTest
+{
+
+	@Test
+	public void test()
+	{
+		Accumulate a = new Accumulate();
+
+		int sum = a.Sum_Solution(4);
+		Assert.assertEquals(10, sum);
+	}
+}

swordForOffer/src/test/java/problem47/AddTwoNumberTest.java

@@ -0,0 +1,19 @@
+package problem47;
+
+import junit.framework.Assert;
+import org.junit.Test;
+
+/**
+ * Created by bjyangrubing on 2016/8/26.
+ */
+public class AddTwoNumberTest
+{
+	@Test
+	public void test()
+	{
+		AddTwoNumber a = new AddTwoNumber();
+
+		Assert.assertEquals(2, a.Add(1, 1));
+	}
+
+}

swordForOffer/src/test/java/problem48/FinalClassTest.java

@@ -0,0 +1,8 @@
+package problem48;
+
+/**
+ * Created by bjyangrubing on 2016/8/26.
+ */
+public class FinalClassTest
+{
+}

swordForOffer/src/test/java/problem49/StrToIntTest.java

@@ -0,0 +1,19 @@
+package problem49;
+
+import junit.framework.Assert;
+import org.junit.Test;
+
+/**
+ * Created by bjyangrubing on 2016/8/26.
+ */
+public class StrToIntTest
+{
+	@Test
+	public void test()
+	{
+		StrToInt s = new StrToInt();
+		Assert.assertEquals(123, s.strToInt("123"));
+		Assert.assertEquals(-123, s.strToInt("-123"));
+		Assert.assertEquals(123, s.strToInt("+123"));
+	}
+}