day 2 p1

Author: Aaryan-Degama

Problems/Mathematics/Day-02/sol/Aaryan_Degama/Solution1.cpp

@@ -0,0 +1,68 @@
+// link : https://codeforces.com/problemset/submission/1771/355643992
+
+#include <bits/stdc++.h>
+using namespace std;
+
+#define fastio ios::sync_with_stdio(false); cin.tie(NULL);
+
+using ll = long long;
+
+void solve() {
+    ll n;
+    cin >> n;
+
+    vector<ll> a(n);
+    for (ll i = 0; i < n; i++) {
+        cin >> a[i];
+    }
+
+    sort(a.begin(), a.end());
+
+    ll i = 1;
+    while (i < n && a[i] == a[i - 1]) i++;
+
+    if (i == n) {
+        cout << n * (n - 1) << "\n";
+        return;
+    }
+
+    ll j = 1;
+    while (j < n && a[n - j] == a[n - j - 1]) j++;
+
+    cout << 2LL * i * j << "\n";
+}
+
+int main() {
+    fastio
+    int t;
+    cin >> t;
+    while (t--) solve();
+}
+
+
+/*
+The maximum possible absolute difference in an array is obtained only by
+choosing the minimum and the maximum elements.
+
+So, all valid pairs must consist of:
+one minimum element
+one maximum element
+
+Approach:
+
+1. Sort the array.
+   Minimum elements appear at the beginning.
+   Maximum elements appear at the end.
+
+2. Count how many times the minimum element appears.
+   Let this count be 'i'.
+
+3. Count how many times the maximum element appears.
+   Let this count be 'j'.
+
+
+
+Time Complexity: O(n log n)
+Space Complexity: O(n)
+
+*/