sqrtx

Author: jackzhenguo

Math/Math.Lib/Sqrtx.cs

@@ -0,0 +1,28 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace Math.Lib
+{
+    public class SqrtSln
+    {
+        public int MySqrt(int x)
+        {
+            int lo = 0, hi = x;
+            while (lo - hi < -1)
+            {
+                //get [lo,hi] middle point,then compare pow2 to x,
+                // lo or hi is setted by mid
+                //so accelarate the process
+                long mid = lo + (hi - lo) / 2; //prevent overflowing
+                long pow2 = mid * mid; //prevent overflowing
+                if (pow2 < x) lo = (int)mid;
+                else if (pow2 > x) hi = (int)mid;
+                else return (int)mid;
+            }
+            return lo;
+        }
+    }
+
+}