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+// 565. Array Nesting
+#include "leetcode.h"
+
+/*
+ * you are given an integer array 'nums' of length 'n' where 'nums' is a
+ * permutation of the numbers in the range '[0, n - 1]'. you should bild a set
+ * 's[k] = {nums[k], nums[nums[k]], ... }' subjected to the following rules: the
+ * first element in 's[k]' starts with the selection of the element 'nums[k]' of
+ * 'index = k'. the next element in 's[k]' should be 'nums[nums[k]]', and so on.
+ * we stop adding right before a duplication element occurs in 's[k]'. return
+ * the longest set of 's[k]'
+ */
+
+int arrayNesting(int *nums, int numsSize) {
+ int max = 0, cnt = 0;
+ for (int i = 0; i < numsSize; i++)
+ if (nums[i] != -1) {
+ int j = nums[i];
+ cnt = 0;
+ while (j != i) {
+ cnt++;
+ int tmp = nums[j];
+ nums[j] = -1;
+ j = tmp;
+ }
+ cnt++;
+ if (cnt > max)
+ max = cnt;
+ }
+ return max;
+}
+
+int main() {
+ int n1[] = {5, 4, 0, 3, 1, 6, 2}, n2[] = {0, 1, 2};
+ printf("%d\n", arrayNesting(n1, ARRAY_SIZE(n1))); // expect: 4
+ printf("%d\n", arrayNesting(n2, ARRAY_SIZE(n2))); // expect: 1
+}