feat: Add efficient binary search solution for square root calculation

easy/sqrtx.test.ts

@@ -0,0 +1,46 @@
+// Problem: https://leetcode.com/problems/sqrtx/description/
+// Doc: https://leetcode.com/problems/sqrtx/solutions/5491801/efficient-binary-search-for-square-root-calculation/
+const mySqrt = (x: number): number => {
+  let [l, r] = [0, 1];
+  // We are not allowed to use Math.pow
+  // So we initialize r using this loop :v
+  for (let i = 1; i <= 31; i++) {
+    r *= i;
+  }
+  r--;
+
+  let ans = 0;
+  while (l <= r) {
+    const m = Math.floor((l + r) / 2);
+
+    if (m * m === x) return m;
+
+    if (m * m > x) {
+      r = m - 1;
+      continue;
+    }
+
+    ans = m;
+    l = m + 1;
+  }
+
+  return ans;
+};
+
+describe('Sqrt(x)', () => {
+  it('should return the square root of x', () => {
+    expect(mySqrt(0)).toBe(0);
+    expect(mySqrt(1)).toBe(1);
+    expect(mySqrt(2)).toBe(1);
+    expect(mySqrt(4)).toBe(2);
+    expect(mySqrt(8)).toBe(2);
+    expect(mySqrt(9)).toBe(3);
+    expect(mySqrt(16)).toBe(4);
+    expect(mySqrt(25)).toBe(5);
+    expect(mySqrt(36)).toBe(6);
+    expect(mySqrt(49)).toBe(7);
+    expect(mySqrt(64)).toBe(8);
+    expect(mySqrt(81)).toBe(9);
+    expect(mySqrt(100)).toBe(10);
+  });
+});