git reimport

archive/2019.03/2019.03.11 - Codeforces Round #546 (Div. 2)/TaskD.java

@@ -0,0 +1,72 @@
+package chelper;
+
+import java.util.ArrayList;
+import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
+
+import io.InputReader;
+import io.OutputWriter;
+import solutions.ChelperSolution;
+
+
+public class TaskD extends ChelperSolution {
+
+  public static final long MAGIC = 1000000L;
+
+  @Override
+  public void solve(int testNumber, InputReader in, OutputWriter out) {
+    super.solve(testNumber, in, out);
+  }
+
+  @Override
+  public void solve(int testNumber) {
+    int n = in.nextInt();
+    int m = in.nextInt();
+
+    int[] positions = in.nextIntArray(n);
+    int[][] swaps = in.nextIntIntArray(m, 2);
+
+    int[] positionOf = new int[n + 1];
+
+    for (int i = 0; i < n; i++) {
+      positionOf[positions[i]] = i;
+    }
+
+    Set<Long> set = new HashSet<>();
+
+    for (int i = 0; i < m; i++) {
+      int l = positionOf[swaps[i][0]];
+      int r = positionOf[swaps[i][1]];
+
+      set.add(l * MAGIC + r);
+    }
+
+    int nastya = n - 1;
+
+    List<Integer> jumpers = new ArrayList<>();
+    List<Integer> leftovers = new ArrayList<>();
+//    Set<Integer> jumpers = new HashSet<>();
+//    Set<Integer> leftovers = new HashSet<>();
+    leftovers.add(nastya);
+
+    for (int i = nastya - 1; i >= 0; i--) {
+      boolean ok = true;
+
+      for (Integer j : leftovers) {
+        if (!set.contains(i * MAGIC + j)) {
+          ok = false;
+          break;
+        }
+      }
+
+      if (ok) {
+        jumpers.add(i);
+      } else {
+        leftovers.add(i);
+      }
+    }
+
+    out.println(jumpers.size());
+  }
+}