update 69

leetcode/69.py

@@ -0,0 +1,22 @@
+# Sqrt(x)
+# Do not use build in operator
+
+
+class Solution:
+    def mySqrt(self, c: int) -> int:
+        # Use Newton's method, return the smaller root
+        # fx = x ** 2 - c
+        # Xn-1 = 0.5 * (Xn + c / Xn)
+        x = c / 2
+        while True:
+            next_x = (x + c / x) / 2
+            if x - next_x > -1 and x - next_x <= 0:
+                break
+            x = next_x
+
+        return int(x)
+
+
+if __name__ == "__main__":
+    print(Solution().mySqrt(13))
+    print(Solution().mySqrt(16))