14 files changed, 41 insertions, 0 deletions
diff --git a/contests/filtrationContest/C/main b/contests/filtrationContest/C/main
new file mode 100755
index 0000000..4fad05f
--- /dev/null
+++ b/contests/filtrationContest/C/main
diff --git a/contests/filtrationContest/C/main.cpp b/contests/filtrationContest/C/main.cpp
new file mode 100644
index 0000000..0d06899
--- /dev/null
+++ b/contests/filtrationContest/C/main.cpp
@@ -0,0 +1,23 @@
+#include<bits/stdc++.h>
+
+using namespace std;
+
+int64_t fq[22];
+
+int main () {
+	ios_base::sync_with_stdio(false);
+	cin.tie(NULL);
+  long long n;
+  cin >> n;
+  for (int i = 1; i <= n; i++) {
+    int64_t x;
+    cin >> x;
+    fq[10 + 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;
+}
diff --git a/contests/filtrationContest/C/main_input0.txt b/contests/filtrationContest/C/main_input0.txt
new file mode 100644
index 0000000..72f399e
--- /dev/null
+++ b/contests/filtrationContest/C/main_input0.txt
@@ -0,0 +1,2 @@
+5
+-3 3 0 0 3
diff --git a/contests/filtrationContest/C/main_input1.txt b/contests/filtrationContest/C/main_input1.txt
new file mode 100644
index 0000000..2edfca6
--- /dev/null
+++ b/contests/filtrationContest/C/main_input1.txt
@@ -0,0 +1,2 @@
+3
+0 0 0
diff --git a/contests/filtrationContest/C/main_input2.txt b/contests/filtrationContest/C/main_input2.txt
new file mode 100644
index 0000000..86d0781
--- /dev/null
+++ b/contests/filtrationContest/C/main_input2.txt
@@ -0,0 +1,2 @@
+7
+-1 1 1 1 0 0 0
+\ No newline at end of file
diff --git a/contests/filtrationContest/C/main_input3.txt b/contests/filtrationContest/C/main_input3.txt
new file mode 100644
index 0000000..91a9d0e
--- /dev/null
+++ b/contests/filtrationContest/C/main_input3.txt
@@ -0,0 +1,2 @@
+6 
+0 0 0 0 0 0
+\ No newline at end of file
diff --git a/contests/filtrationContest/C/main_input4.txt b/contests/filtrationContest/C/main_input4.txt
new file mode 100644
index 0000000..9dd1093
--- /dev/null
+++ b/contests/filtrationContest/C/main_input4.txt
@@ -0,0 +1,2 @@
+4
+1 -1 1 -1
+\ No newline at end of file
diff --git a/contests/filtrationContest/C/main_input5.txt b/contests/filtrationContest/C/main_input5.txt
new file mode 100644
index 0000000..166c057
--- /dev/null
+++ b/contests/filtrationContest/C/main_input5.txt
@@ -0,0 +1,2 @@
+1
+0
+\ No newline at end of file
diff --git a/contests/filtrationContest/C/main_output0.txt b/contests/filtrationContest/C/main_output0.txt
new file mode 100644
index 0000000..00750ed
--- /dev/null
+++ b/contests/filtrationContest/C/main_output0.txt
@@ -0,0 +1 @@
+3
diff --git a/contests/filtrationContest/C/main_output1.txt b/contests/filtrationContest/C/main_output1.txt
new file mode 100644
index 0000000..00750ed
--- /dev/null
+++ b/contests/filtrationContest/C/main_output1.txt
@@ -0,0 +1 @@
+3
diff --git a/contests/filtrationContest/C/main_output2.txt b/contests/filtrationContest/C/main_output2.txt
new file mode 100644
index 0000000..ca7bf83
--- /dev/null
+++ b/contests/filtrationContest/C/main_output2.txt
@@ -0,0 +1 @@
+13
+\ No newline at end of file
diff --git a/contests/filtrationContest/C/main_output3.txt b/contests/filtrationContest/C/main_output3.txt
new file mode 100644
index 0000000..3f10ffe
--- /dev/null
+++ b/contests/filtrationContest/C/main_output3.txt
@@ -0,0 +1 @@
+15
+\ No newline at end of file
diff --git a/contests/filtrationContest/C/main_output4.txt b/contests/filtrationContest/C/main_output4.txt
new file mode 100644
index 0000000..bf0d87a
--- /dev/null
+++ b/contests/filtrationContest/C/main_output4.txt
@@ -0,0 +1 @@
+4
+\ No newline at end of file
diff --git a/contests/filtrationContest/C/main_output5.txt b/contests/filtrationContest/C/main_output5.txt
new file mode 100644
index 0000000..c227083
--- /dev/null
+++ b/contests/filtrationContest/C/main_output5.txt
@@ -0,0 +1 @@
+0
+\ No newline at end of file