done 3 sorting problems

CSES - CSES Problem Set/Distinct_Numbers.cpp

@@ -0,0 +1,19 @@
+//  Distinct Numbers
+
+#include<bits/stdc++.h>
+
+using namespace std;
+using ll = long long;
+
+int main() {
+    int count = 1;
+    int n; cin >> n;
+    vector<ll> i(n);
+    for (auto &e: i) cin >> e;
+    std::sort(i.begin(), i.end());
+    for (int j = 1; j < i.size(); j++) {
+        if (i[j] != i[j-1]) count ++;
+    }
+    cout << count << endl;
+    return 0;
+}