😓: 367

Author: withrvr

Problem/Easy/301-400/367. Valid Perfect Square/_a.java

@@ -0,0 +1,15 @@
+// build in math func
+// a.java ... more better
+
+// To Code : 3 min
+// Execution : ? ms
+
+// Time complexity: O(1)
+// Space complexity: O(1)
+
+class Solution {
+public boolean isPerfectSquare(int num) {
+int val = (int) Math.pow(num, 0.5);
+return num == val * val;
+}
+}

Problem/Easy/301-400/367. Valid Perfect Square/a.java

@@ -0,0 +1,14 @@
+// build in math func
+
+// To Code : 3 min
+// Execution : ? ms
+
+// Time complexity: O(1)
+// Space complexity: O(1)
+
+class Solution {
+public boolean isPerfectSquare(int num) {
+float val = (float) Math.sqrt(num);
+return (int) val == val;
+}
+}

Problem/Easy/301-400/367. Valid Perfect Square/b.java

@@ -0,0 +1,10 @@
+// check if last char is zero
+// but don't use it
+// just a logic
+
+class Solution {
+public boolean isPerfectSquare(int num) {
+String val = String.valueOf(Math.sqrt(num));
+return val.charAt(val.length() - 1) == '0';
+}
+}

Problem/Easy/301-400/367. Valid Perfect Square/c.java

@@ -0,0 +1,22 @@
+// binary search
+
+class Solution {
+public boolean isPerfectSquare(int num) {
+long start = 1;
+long end = num;
+
+while (start <= end) {
+long mid = start + (end - start) / 2;
+long mul = mid * mid;
+
+if (mul == num)
+return true;
+else if (mul > num)
+end = mid - 1;
+else
+start = mid + 1;
+}
+
+return false;
+}
+}

Problem/Easy/301-400/367. Valid Perfect Square/d.java

@@ -0,0 +1,13 @@
+// Newton Method
+
+class Solution {
+public boolean isPerfectSquare(int num) {
+long x = num;
+
+while (x * x > num) {
+x = (x + num / x) >> 1;
+}
+
+return x * x == num;
+}
+}

Problem/Easy/301-400/367. Valid Perfect Square/readme.md

@@ -0,0 +1,15 @@
+# 📄: 367. Valid Perfect Square
+
+- https://leetcode.com/study-plan/binary-search/?progress=x31a8njd
+
+# ✅: Solution
+
+- `https://leetcode.com/problems/valid-perfect-square/solutions/130010/python-4-methods-with-time-testing/`
+-
+- a ... build in .... int check
+ - b ... pow ... mul check
+- b ... out of the box / but don't use it
+-
+- c ... binary search
+- d ... Newton Method
+-

template/a.java

@@ -1,6 +1,4 @@
-// logic
-
-// explanation
+// logic, explanation
 
 // To Code : ? min
 // Execution : ? ms