feat: 69_sqrt_x

69_sqrt_x/main.cpp

@@ -0,0 +1,27 @@
+#include <bits/stdc++.h>
+using namespace std;
+
+class Solution {
+   public:
+    int mySqrt(int x) {
+        if (x == 1) return 1;
+
+        long long l = 0, r = x;
+
+        while (true) {
+            long long m = (l + r) / 2;
+            if (m * m > x) {
+                r = m;
+            } else if (m * m < x) {
+                if ((m + 1) * (m + 1) > x) {
+                    return m;
+                }
+                l = m;
+            } else {
+                return m;
+            }
+        }
+
+        return 0;
+    }
+};