add 70, 1414, 2185, update 509

Author: rustykitty

0070-climbing-stairs.c

@@ -0,0 +1,19 @@
+/*
+70. Climbing Stairs
+
+Submitted: January 9th, 2025
+
+Runtime: 0 ms (beats 100.00%)
+Memory: 7.75 MB (beats 54.99%)
+*/
+
+int cache[45] = { 0 };
+int climbStairs(int n) {
+    if (n == 0 || n == 1) {
+        return 1;
+    }
+    if (cache[n - 1] != 0) return cache[n - 1];
+    int res = climbStairs(n - 2) + climbStairs(n - 1);
+    if (cache[n - 1] == 0) cache[n - 1] = res;
+    return res;
+}

0070-climbing-stairs.cpp

@@ -0,0 +1,22 @@
+/*
+70. Climbing Stairs
+
+Submitted: January 9th, 2025
+
+Runtime: 0 ms (beats 100.00%)
+Memory: 7.97 MB (beats 43.48%)
+*/
+
+class Solution {
+public:
+    int cache[45] = { 0 };
+    int climbStairs(int n) {
+        if (n == 0 || n == 1) {
+            return 1;
+        }
+        if (cache[n - 1] != 0) return cache[n - 1];
+        int res = climbStairs(n - 2) + climbStairs(n - 1);
+        if (cache[n - 1] == 0) cache[n - 1] = res;
+        return res;
+    }
+};

0070-climbing-stairs.py

@@ -0,0 +1,16 @@
+"""
+70. Climbing Stairs
+
+Submitted: January 9th, 2025
+
+Runtime: 1 ms (beats 3.84%)
+Memory: 17.59 MB (beats 37.71%)
+"""
+
+class Solution:
+    @functools.lru_cache(maxsize=45)
+    def climbStairs(self, n: int) -> int:
+        if n == 0 or n == 1:
+            return 1
+        else:
+            return self.climbStairs(n - 1) + self.climbStairs(n - 2)

0509-fibonacci-number.c

@@ -0,0 +1,18 @@
+/*
+509. Fibonacci Number
+
+Submitted: January 9, 2025
+
+Runtime: 3 ms (beats 60.33%)
+Memory: 7.74 MB (beats 42.31%)
+*/
+
+int cache[30] = { 0 };
+int fib(int n) {
+    if (n == 0) return 0;
+    if (n == 1 || n == 2) return 1;
+    if (cache[n - 1] != 0) return cache[n - 1];
+    int res = fib(n - 2) + fib(n - 1);
+    if (cache[n - 1] == 0) cache[n - 1] = res;
+    return res;
+}

0509-fibonacci-number.cpp

@@ -1,15 +1,21 @@
 /*
 509. Fibonacci Number
 
-Submitted: October 24, 2024
+Submitted: January 10, 2024
 
-Runtime: 11 ms (beats 43.59%)
-Memory: 7.19 MB (beats 98.56%)
+Runtime: 3 ms (beats 65.66%)
+Memory: 7.61 MB (beats 68.47%)
 */
 
 class Solution {
 public:
+    int cache[30] = { 0 };
     int fib(int n) {
-        return n < 2 ? n : (fib(n - 1) + fib(n - 2));
+        if (n == 0) return 0;
+        if (n == 1 || n == 2) return 1;
+        if (cache[n - 1] != 0) return cache[n - 1];
+        int res = fib(n - 2) + fib(n - 1);
+        if (cache[n - 1] == 0) cache[n - 1] = res;
+        return res;
     }
-};
+};

0509-fibonacci-number.py

@@ -3,11 +3,12 @@
 
 Submitted: October 24, 2024
 
-Runtime: 977 ms (beats 5.12%)
-Memory: 13.87 MB (beats 100.00%)
+Runtime: 38 ms (beats 57.81%)
+Memory: 17.66 MB (beats 24.28%)
 """
 
 class Solution:
+    @functools.cache
     def fib(self, n: int) -> int:
         if n == 0 or n == 1:
             return n

1414-find-the-minimum-number-of-fibonacci-numbers-whose-sum-is-k.c

@@ -0,0 +1,41 @@
+/*
+1414. Find the Minimum Number of Fibonacci Numbers Whose Sum Is K
+
+Submitted: January 9, 2025
+
+Runtime: 1 ms (beats 11.11%)
+Memory: 8.16 MB (beats 77.78%)
+*/
+
+#define SIZE 45
+
+int cache[SIZE + 1];
+
+int _helper(int);
+int cached_fib(int);
+
+int findMinFibonacciNumbers(int k) {
+    for (int i = 0; i < SIZE + 1; ++i) {
+        cached_fib(i);
+    }
+    return _helper(k);
+}
+
+int _helper(int k) {
+    if (k == 0) return 0;
+    if (k == 1) return 1;
+    for (int i = 0; i < SIZE; ++i) {
+        if (cache[SIZE - i - 1] <= k) {
+            return _helper(k - cache[SIZE - i - 1]) + 1;
+            break;
+        }
+    }
+    return -1; // should never get here
+}
+
+int cached_fib(int n) {
+    if (n == 0) return 0;
+    if (n == 1 || n == 2) return 1;
+    if (cache[n-1] != 0) return cache[n-1];
+    return (cache[n-1] = (cached_fib(n - 1) + cached_fib(n - 2)));
+}

2185-counting-words-with-a-given-prefix.c

@@ -0,0 +1,18 @@
+/*
+2185. Counting Words with a Given Prefix
+
+LeetCode Daily Question for January 9, 2025
+
+Runtime: 0 ms (beats 100.00%)
+Memory: 8.86 
+*/
+
+int prefixCount(char** words, int wordsSize, char* pref) {
+    int res = 0;
+    int pref_len = strlen(pref); // get length of prefix
+    for (int i = 0; i < wordsSize; ++i) {
+        // compare prefix with first pref_len characters of each word
+        res += (strncmp(words[i], pref, pref_len) == 0);
+    }
+    return res;
+}

2185-counting-words-with-a-given-prefix.py

@@ -0,0 +1,12 @@
+"""
+2185. Counting Words with a Given Prefix
+
+LeetCode Daily Question for January 9, 2025
+
+Runtime: 0 ms (beats 100.00%)
+Memory: 17.86 MB (beats 20.89%)
+"""
+
+class Solution:
+    def prefixCount(self, words: List[str], pref: str) -> int:
+        return sum(s.startswith(pref) for s in words)