AddBinary and ExcelColumnTitle

Author: jackzhenguo

Math/Math.Lib/AddBinarySln.cs

@@ -0,0 +1,54 @@
+/* ==============================================================================
+ * 功能描述：AddBinary  
+ * 创 建 者：gz
+ * 创建日期：2017/5/23 12:57:28
+ * ==============================================================================*/
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Math.Lib
+{
+    // Given two binary strings, return their sum (also a binary string).
+    //For example,
+    //a = "11"
+    //b = "1"
+    //Return "100".
+    /// <summary>
+    /// AddBinary
+    /// </summary>
+    public class AddBinarySln
+    {
+        public string AddBinary(string a, string b)
+        {
+            StringBuilder sb = new StringBuilder();
+            int carry = 0, acnt = a.Length, bcnt = b.Length;
+            for (int i = acnt - 1, j = bcnt - 1; i >= 0 || j >= 0 || carry == 1; i--, j--){           
+                int sum2 = 0;
+                if (i < 0 && j < 0){ //overflow solving               
+                    sb.Append(carry);
+                    carry = 0;
+                    continue;
+                }
+                //discuss three conditions according to i and j
+                if (i < 0) sum2 = b[j] - '0';
+                else if (j < 0) sum2 = a[i] - '0';
+                else sum2 = a[i] - '0' + b[j] - '0';
+                if (sum2 + carry < 2){
+                    sb.Append(sum2 + carry);
+                    carry = 0;
+                }
+                else {
+                    sb.Append(sum2 + carry - 2);
+                    carry = 1;
+                }
+            }
+            //reverse the sb
+            IEnumerable<char> rtnchars = sb.ToString().Reverse();
+            sb.Clear();
+            foreach (var ch in rtnchars) sb.Append(ch);
+            return sb.ToString();
+        }
+    }
+}

Math/Math.Lib/ExcelColumnTitle.cs

@@ -0,0 +1,39 @@
+/* ==============================================================================
+ * 功能描述：Class1  
+ * 创 建 者：gz
+ * 创建日期：2017/5/23 12:49:30
+ * ==============================================================================*/
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Math.Lib
+{
+    /// <summary>
+    /// ExcelColumnTitle
+    /// </summary>
+    public class ExcelColumnTitle
+    {
+        public string ConvertToTitle(int n)
+        {
+            //A~Z:26
+            //AA~ZZ:26*26
+            //...
+            if (n == 1) return "A";
+            char[] chdict = {'A','B','C','D','E','F','G','H','I','J','K', 'L','M','N','O','P','Q','R','S','T','U','V','W','X','Y','Z'};        
+            StringBuilder sb = new StringBuilder();
+            while (n > 0)
+            {
+                n--; //beacuse our chdict's index begins Zero.
+                sb.Append(chdict[n % 26]);
+                n = n / 26;
+            }
+            IEnumerable<char> rtnchars = sb.ToString().Reverse();
+            sb.Clear();
+            foreach (var ch in rtnchars) sb.Append(ch);               
+            return sb.ToString();
+        }
+
+    }
+}