git reimport

archive/2017.09/2017.09.18 - unsorted/M.java

@@ -0,0 +1,31 @@
+package chelper;
+
+import io.InputReader;
+import io.OutputWriter;
+import misc.SimpleSavingChelperSolution;
+
+
+public class M extends SimpleSavingChelperSolution {
+
+  public void solve(int testNumber, InputReader in, OutputWriter out) {
+    wrapSolve(testNumber, in, out);
+  }
+
+  @Override
+  public void solve(int testNumber) {
+    int n = in.nextInt();
+
+    int[] a = in.nextIntArray(n);
+
+    boolean ok = true;
+    int d = a[1] - a[0];
+
+    for (int i = 0; i < n - 1; i++) {
+      int t = a[i + 1] - a[i];
+
+      ok &= t == d;
+    }
+
+    out.println(ok ? (a[n - 1] + d) : a[n - 1]);
+  }
+}