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authorJack Sangdahl <[email protected]>2024-07-04 20:53:10 -0600
committerJack Sangdahl <[email protected]>2024-07-04 20:53:10 -0600
commit08acd45da0244d0be7e59977e3427da7aefc8ac4 (patch)
tree10bcb216678131e074597e45a6afbbecc1f7fd7c
parent1d8e4b171520eba615ef98d63a01e94620142057 (diff)
downloadleetcode-08acd45da0244d0be7e59977e3427da7aefc8ac4.tar.gz
leetcode-08acd45da0244d0be7e59977e3427da7aefc8ac4.zip
2058. find the minimum & maximum number of nodes between critical points
-rw-r--r--find_min_max_nodes_crit.c67
-rw-r--r--find_min_max_nodes_crit.py41
2 files changed, 108 insertions, 0 deletions
diff --git a/find_min_max_nodes_crit.c b/find_min_max_nodes_crit.c
new file mode 100644
index 0000000..773eff9
--- /dev/null
+++ b/find_min_max_nodes_crit.c
@@ -0,0 +1,67 @@
+// 2058. Find the Minimum and Maximum Number of Nodes Between Critical Points
+#include "leetcode.h"
+
+/*
+ * a critical point in a linked list is defined as either a local maxima or a
+ * local minima. anode is a local maxima if the current node has a value
+ * strictly greater than the previous node and the next node. a node is a minima
+ * if the current node has a value strictly smaller than the previous node and
+ * the next node. note that a node can only be a local maxima/minima if there
+ * exists both a previous node and a next node. given a linked list 'head',
+ * return an array of length 2 container '[min_distance, max_distance]' where
+ * 'min_distance' is the minimum distance between any two distinct nodes and
+ * oppositely true for 'max_distance'. if there are fewer than two critical
+ * points, return '[-1, -1]'
+ */
+
+struct ListNode {
+ int val;
+ struct ListNode *next;
+};
+
+/**
+ * Note: The returned array must be malloced, assume caller calls free().
+ */
+int *nodesBetweenCriticalPoints(struct ListNode *head, int *returnSize) {
+ int first = INT_MAX, last = 0, prev_val = head->val, min_d = INT_MAX;
+ for (int i = 0; head->next; ++i) {
+ if (fmax(prev_val, head->next->val) < head->val ||
+ fmin(prev_val, head->next->val)) {
+ if (last)
+ min_d = fmin(min_d, i - last);
+ first = fmin(first, i);
+ last = i;
+ }
+ prev_val = head->val;
+ head = head->next;
+ }
+ int *ans = (int *)malloc(2 * sizeof(int));
+ if (min_d == INT_MAX)
+ ans[0] = -1, ans[1] = -1;
+ else
+ ans[0] = min_d, ans[1] = last - first;
+ return ans;
+}
+
+struct ListNode *create_node(int val) {
+ struct ListNode *new = (struct ListNode *)malloc(sizeof(struct ListNode));
+ new->val = val;
+ new->next = NULL;
+ return new;
+}
+
+int main() {
+ int rs1;
+ struct ListNode *head = create_node(5);
+ head->next = create_node(3);
+ head->next->next = create_node(1);
+ head->next->next->next = create_node(2);
+ head->next->next->next->next = create_node(5);
+ head->next->next->next->next->next = create_node(1);
+ head->next->next->next->next->next->next = create_node(2);
+ int *ndcp1 = nodesBetweenCriticalPoints(head, &rs1);
+ for (int i = 0; i < rs1; i++)
+ printf("%d ", ndcp1[i]); // expect: 1 3
+ printf("\n");
+ free(ndcp1);
+}
diff --git a/find_min_max_nodes_crit.py b/find_min_max_nodes_crit.py
new file mode 100644
index 0000000..5e66284
--- /dev/null
+++ b/find_min_max_nodes_crit.py
@@ -0,0 +1,41 @@
+# 2058. Find the Minimum and Maximum Number of Nodes Between Critical Points
+
+"""
+a critical point in a linked list is defined as either a local maxima or a
+local minima. anode is a local maxima if the current node has a value
+strictly greater than the previous node and the next node. a node is a minima
+if the current node has a value strictly smaller than the previous node and
+the next node. note that a node can only be a local maxima/minima if there
+exists both a previous node and a next node. given a linked list 'head',
+return an array of length 2 container '[min_distance, max_distance]' where
+'min_distance' is the minimum distance between any two distinct nodes and
+oppositely true for 'max_distance'. if there are fewer than two critical
+points, return '[-1, -1]'
+"""
+
+
+# Definition for singly-linked list.
+class ListNode(object):
+ def __init__(self, val=0, next=None):
+ self.val = val
+ self.next = next
+
+
+class Solution(object):
+ def nodesBetweenCriticalPoints(self, head):
+ """
+ :type head: Optional[ListNode]
+ :rtype: List[int]
+ """
+ crit, crit_pt, prev = 0, [], head.val
+ while head.next:
+ if (prev - head.val) * (head.val - head.next.val) < 0:
+ crit_pt.append(crit)
+ prev, head = head.val, head.next
+ crit += 1
+ n = len(crit_pt)
+ if n < 2:
+ return [-1, -1]
+ mn = min((crit_pt[i] - crit_pt[i - 1] for i in range(1, n)))
+ mx = crit_pt[-1] - crit_pt[0]
+ return [mn, mx]