leetcode

commit a0030873dabb517594ae0394350d6715071f7fb8
parent 8a4cccf73263daae2a4c19f2bfa41cf96187ad56
Author: Jack Sangdahl <jack@pngu.org>
Date:   Sun,  2 Feb 2025 22:27:19 -0700

3105. longest strictly increasing or strictly decreasing subarray

Diffstat:
A
long_strictly_incr_decr_subarr.c
 | 
26
++++++++++++++++++++++++++
A
long_strictly_incr_decr_subarr.py
 | 
29
+++++++++++++++++++++++++++++

2 files changed, 55 insertions(+), 0 deletions(-)
diff --git a/long_strictly_incr_decr_subarr.c b/long_strictly_incr_decr_subarr.c
@@ -0,0 +1,26 @@
+// 3105. Longest Strictly Increasing or Strictly Decreasing Subarray
+#include "leetcode.h"
+
+/*
+ * you are given an array of integers 'nums'. return the legnth of the longest
+ * subarray of 'nums' which is either strictly increasing or strictly
+ * decreasing.
+ */
+
+int longestMonotonicSubarray(int *nums, int numsSize) {
+  int ans = 1, inc = 1, dec = 1;
+  for (int i = 1; i < numsSize; i++) {
+    bool a = nums[i] > nums[i - 1], b = nums[i] < nums[i - 1];
+    inc = a * inc + 1;
+    dec = b * dec + 1;
+    ans = fmax(ans, fmax(inc, dec));
+  }
+  return ans;
+}
+
+int main() {
+  int n1[] = {1, 4, 3, 3, 2}, n2[] = {3, 3, 3, 3}, n3[] = {3, 2, 1};
+  printf("%d\n", longestMonotonicSubarray(n1, ARRAY_SIZE(n1))); // expect: 2
+  printf("%d\n", longestMonotonicSubarray(n2, ARRAY_SIZE(n2))); // expect: 1
+  printf("%d\n", longestMonotonicSubarray(n3, ARRAY_SIZE(n3))); // expect: 3
+}
diff --git a/long_strictly_incr_decr_subarr.py b/long_strictly_incr_decr_subarr.py
@@ -0,0 +1,29 @@
+# 3105. Longest Strictly Increasing or Strictly Decreasing Subarray
+
+"""
+you are given an array of integers 'nums'. return the legnth of the longest
+subarray of 'nums' which is either strictly increasing or strictly
+decreasing.
+"""
+
+
+class Solution(object):
+    def longestMonotonicSubarray(self, nums):
+        """
+        :type nums: List[int]
+        :rtype: int
+        """
+        n, ans, inc, dec = len(nums), 1, 1, 1
+        for i in range(1, n):
+            a, b = nums[i] > nums[i - 1], nums[i] < nums[i - 1]
+            inc = a * inc + 1
+            dec = b * dec + 1
+            ans = max(ans, dec, inc)
+        return ans
+
+
+if __name__ == "__main__":
+    obj = Solution()
+    print(obj.longestMonotonicSubarray(nums=[1, 4, 3, 3, 2]))
+    print(obj.longestMonotonicSubarray(nums=[3, 3, 3, 3]))
+    print(obj.longestMonotonicSubarray(nums=[3, 2, 1]))