git reimport

archive/2017.01/2017.01.10 - unsorted/TaskK.java

@@ -0,0 +1,97 @@
+package chelper;
+
+import java.math.BigInteger;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.List;
+
+import io.InputReader;
+import io.OutputWriter;
+
+public class TaskK {
+  public void solve(int testNumber, InputReader in, OutputWriter out) {
+    int n = in.nextInt();
+    int[] a = new int[n];
+    int[] b = new int[n];
+    for (int i = 0; i < n; i++) {
+      a[i] = in.nextInt() - 1;
+    }
+    for (int i = 0; i < n; i++) {
+      b[i] = in.nextInt() - 1;
+    }
+    int[][] position = new int[2][n];
+    Arrays.fill(position[0], -1);
+    for (int i = 0; i < n; i++) {
+      int x = a[i];
+      if (position[0][x] == -1) {
+        position[0][x] = i;
+      } else {
+        position[1][x] = i;
+      }
+    }
+    for (int i = 0; i < n; i++) {
+      int x = b[i];
+      if (position[0][x] == -1) {
+        position[0][x] = i + n;
+      } else {
+        position[1][x] = i + n;
+      }
+    }
+    List<String> answer = new ArrayList<>();
+    for (int i = 0; i < n; i++) {
+      if (a[i] == b[i]) {
+        continue;
+      }
+      int x = a[i];
+      int pos = position[0][x] == i ? position[1][x] : position[0][x];
+      if (pos < n) {
+        answer.add((pos + 1) + " " + (i + 1));
+        int c = b[i];
+        a[pos] = c;
+        b[i] = x;
+        if (position[0][x] == i) {
+          position[1][x] = i + n;
+        } else {
+          position[0][x] = i + n;
+        }
+        if (position[0][c] == i + n) {
+          position[0][c] = pos;
+        } else {
+          position[1][c] = pos;
+        }
+      } else {
+        pos -= n;
+        answer.add((pos + 1) + " " + (pos + 1));
+        answer.add((pos + 1) + " " + (i + 1));
+        int c = b[i];
+        int d = a[pos];
+        int posx1 = i;
+        int posc = i + n;
+        int posd = pos;
+        int posx2 = pos + n;
+        a[pos] = c;
+        b[i] = x;
+        b[pos] = d;
+        if (position[0][x] == posx1) {
+          position[1][x] = posc;
+        } else {
+          position[0][x] = posc;
+        }
+        if (position[0][c] == posc) {
+          position[0][c] = posd;
+        } else {
+          position[1][c] = posd;
+        }
+        if (position[0][d] == posd) {
+          position[0][d] = posx2;
+        } else {
+          position[1][d] = posx2;
+        }
+      }
+    }
+    out.println(answer.size());
+    for (String s : answer) {
+      out.println(s);
+    }
+  }
+}