Add algorithm contest 3.

1 files changed, 34 insertions, 0 deletions

diff --git a/algorithm-contest-3/code/4.cpp b/algorithm-contest-3/code/4.cpp
new file mode 100644
index 0000000..aebd735
--- /dev/null
+++ b/algorithm-contest-3/code/4.cpp
@@ -0,0 +1,34 @@
+#include <algorithm>
+#include <iostream>
+#include <numeric>
+
+int gcd(int a, int b) { return b ? gcd(b, a % b) : a; }
+
+int N;
+int A[100010];
+
+int main() {
+  std::ios_base::sync_with_stdio(false);
+  std::cin.tie(nullptr);
+
+  std::cin >> N;
+
+  for (int i = 0; i < N; i++) {
+    std::cin >> A[i];
+  }
+
+  std::sort(A, A + N);
+
+  int g = A[1] - A[0];
+  for (int i = 1; i < N - 1; i++) {
+    g = gcd(g, A[i + 1] - A[i]);
+  }
+
+  if (g == 0) {
+    std::cout << N;
+  } else {
+    std::cout << (A[N - 1] - A[0]) / g + 1;
+  }
+
+  return 0;
+}