Add solution for Codeforces problem 1771

Implement solution for Codeforces problem 1771 with input handling, sorting, and calculating maximum difference pairs.

Author: Coldesy

Problems/Mathematics/Day-02/Lakshmish/Solution1.cpp

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+//https://codeforces.com/problemset/submission/1771/355264331
+//time complexity:O(t*n*nlogn)because of for loop and sort function
+//space complexity:O(1) not counting input
+#include <bits/stdc++.h>
+using namespace std;
+
+int main() {
+    int t;
+    cin >> t;
+    while (t--) {
+        int n;
+        cin >> n;
+        vector <int> a;
+        for (int i = 0; i < n; i++) {
+            int x;
+            cin >> x;
+            a.push_back(x);//input
+        }
+        sort(a.begin(), a.end());//sorting
+        long long last = 0;
+        long long first = 0; // maximum difference is from first and last element 
+        if(a[0]==a[n-1]){
+            
+            cout<<(n*(n-1))<<endl;//if all elements are same,max diff is 0 so we output number of ordered pairs
+        }
+        else {
+            for (int i = 0; i < n; i++) {
+                if (a[i] == a[n - 1]) {//number of last(high) element repeated
+                    last++;  
+                }
+                else if (a[i] == a[0]) { // number of first(low)element repeated
+                    first++;
+                }
+            }
+
+            cout << 2 * last * first << endl; //2 indicates ordered pair
+        }
+    }
+
+}