1 files changed, 11 insertions, 15 deletions
diff --git a/contests/filtrationContest/C/main.cpp b/contests/filtrationContest/C/main.cpp
index 0d06899..e3ed80c 100644
--- a/contests/filtrationContest/C/main.cpp
+++ b/contests/filtrationContest/C/main.cpp
@@ -1,23 +1,19 @@
 #include<bits/stdc++.h>
-
+ 
 using namespace std;
-
-int64_t fq[22];
-
+ 
 int main () {
-	ios_base::sync_with_stdio(false);
-	cin.tie(NULL);
+  ios_base::sync_with_stdio(false);
+  cin.tie(NULL);
   long long n;
   cin >> n;
-  for (int i = 1; i <= n; i++) {
-    int64_t x;
+  long long ans = 0;
+  map<long long, long long> fq;
+  for(int i = 0; i < n; i++) {
+    long long x;
     cin >> x;
-    fq[10 + x]++;
+    ans += fq[x];
+    fq[-x]++;
   }
-  int64_t ans = 0;
-  for (int i = 1;i <= 10; i++) {
-    ans += fq[10 - i] * fq[10 + i];
-  }
-  ans += fq[10] * (fq[10] - 1) / 2;
-  cout << ans;
+  cout << ans << '\n';
 }