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authorjack <[email protected]>2024-06-14 13:13:15 -0600
committerjack <[email protected]>2024-06-14 13:13:15 -0600
commitd343a3b18dbaca9297d4f7b2280c4a16f0a5c8aa (patch)
tree96df922dae2a5073d9a50ea70c7aae6aa37e3ebe /count_distinct_int.cpp
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+// 2442. Count Number of Distinct Integers After Reverse Operations
+#include "leetcode.h"
+
+/*
+ * array nums contains positive integers
+ * take each integer in array and reverse its digits (eg. 13 -> 31)
+ * then *add* it to end of array. return number of distinct integers.
+ * [1,13,10,12,31] becomes [1,13,10,12,31,1,31,1,21,13]
+ * and total num of distinct ints = 6
+ */
+
+class Solution {
+public:
+ int countDistinctIntegers(vector<int> &nums) {
+ // unordered set constructor to insert 'nums'
+ // note: a set only maintains unique values in it
+ unordered_set<int> us(nums.begin(), nums.end());
+ // find reverse of every num
+ for (auto i : nums) {
+ int n = 0;
+ while (i) {
+ int rem = i % 10;
+ n = n * 10 + rem;
+ i /= 10;
+ }
+ // insert (to end) reverse
+ us.insert(n);
+ }
+ // we can simply return the size since
+ // every element in a set is unique
+ return us.size();
+ }
+};
+
+int main() {
+ Solution obj;
+ vector<int> nums1 = {1, 13, 10, 12, 31}, nums2 = {2, 2, 2};
+ cout << obj.countDistinctIntegers(nums1) << endl; // expect: 6
+ cout << obj.countDistinctIntegers(nums2) << endl; // expect: 1
+}