add 46, 65, update 146

rustykitty · rustykitty · commit 0b06dd47688c · 2025-01-24T07:11:22.000-08:00
diff --git a/0046-permutations.py b/0046-permutations.py
@@ -0,0 +1,12 @@
+"""
+46. Permutations
+
+Submitted: January 23, 2025
+
+Runtime: 0 ms (beats 100.00%)
+Memory: 17.71 MB (beats 60.66%)
+"""
+
+class Solution:
+    def permute(self, nums: List[int]) -> List[List[int]]:
+        return list(permutations(nums))
diff --git a/0065-valid-number.md b/0065-valid-number.md
@@ -0,0 +1,29 @@
+# 65. Valid Number
+
+## Approach
+
+I used the regular expression shown below:
+
+```regex
+(\+|-)?(\d+\.?|(\d+)?\.\d+)((e|E)(\+|-)?\d+)?
+```
+
+### Breakdown of Regex
+
+`(\+|-)?` - an optional plus (`+`) or minus (`-`) sign
+`(\d+\.?|(\d+)?\.\d+)` - the digits, matches one of either:
+- `\d+\.?` - at least one numeric digit and optionally a following decimal dot (e.g. `123`, `123.`)
+- `(\d+)?\.\d+` - a decimal dot and at least one numeric digit, optionally preceded by digits (e.g. `0.33`, `.33`)
+`((e|E)(\+|-)?\d+)?` - the exponent:
+- `(e|E)` matches either uppercase or lowercase `e`
+- `(\+|-)` - see above
+- `\d+` - at least one numeric digit
+- the `?` at the end makes it optional
+
+## Code
+
+```python3
+class Solution:
+    def isNumber(self, s: str) -> bool:
+        return bool(re.fullmatch(r'(\+|-)?(\d+\.?|(\d+)?\.\d+)((e|E)(\+|-)?\d+)?', s))
+```
diff --git a/0065-valid-number.py b/0065-valid-number.py
@@ -0,0 +1,12 @@
+"""
+65. Valid Number
+
+Submitted: January 23, 2025
+
+Runtime: 0 ms (beats 100.00%)
+Memory: 17.60 MB (beats 49.99%)
+"""
+
+class Solution:
+    def isNumber(self, s: str) -> bool:
+        return bool(re.fullmatch(r'(\+|-)?(\d+\.?|(\d+)?\.\d+)((e|E)(\+|-)?\d+)?', s))
diff --git a/0146-lru-cache.java b/0146-lru-cache.java
@@ -0,0 +1,28 @@
+/*
+146. LRU Cache
+
+Submitted: January 23, 2025
+
+Runtime: 40 ms (beats 98.63%)
+Memory: 111.70 MB (beats 89.29%)
+*/
+
+class LRUCache extends LinkedHashMap<Integer, Integer> {
+
+    private final int maxSize;
+
+
+    LRUCache(int maxSize) {
+        super(maxSize, 0.75f, true); // 0.75f is default load factor; true is for accessOrder
+        this.maxSize = maxSize;
+    }
+
+    public int get(int key) {
+        return getOrDefault(key, -1);
+    }
+
+    @Override
+    protected boolean removeEldestEntry(Map.Entry<Integer, Integer> ignore) {
+        return size() > maxSize;
+    }
+}
