git reimport

archive/2018.02/2018.02.17 - unsorted/TaskD.java

@@ -0,0 +1,102 @@
+package chelper;
+
+import io.InputReader;
+import io.OutputWriter;
+import misc.GCJSolution;
+import misc.SimpleSavingChelperSolution;
+
+
+public class TaskD extends GCJSolution {
+
+  public void solve(int testNumber, InputReader in, OutputWriter out) {
+    wrapSolve(testNumber, in, out);
+  }
+
+  double[][][] dp;
+
+  public TaskD() {
+    super();
+    dp = new double[101][101][101];
+
+    for (int c = 0; c <= 100; c++) {
+      for (int b = 0; b <= 100; b++) {
+        for (int a = 0; a <= 100; a++) {
+          dp[a][b][c] = Double.NaN;
+        }
+      }
+    }
+
+    dp[0][0][0] = 0;
+
+    get(0, 0, 100);
+
+//    for (int c = 0; c <= 2; c++) {
+//      for (int b = 0; b <= 2; b++) {
+//        for (int a = 0; a <= 2; a++) {
+//          System.out.println(a + " " + b + " " + c + " " + dp[a][b][c]);
+//        }
+//      }
+//    }
+  }
+
+  @Override
+  public void solve(int testNumber) {
+    int n = in.nextInt();
+
+    out.println(get(0, 0, n));
+  }
+
+  double get(int a, int b, int c) {
+    if (a < 0 || b < 0 || c < 0) {
+      return 0;
+    }
+
+    if (Double.isNaN(dp[a][b][c])) {
+      calc(a, b, c);
+    }
+
+    return dp[a][b][c];
+  }
+
+  void calc(int a, int b, int c) {
+    double aa = a;
+    double bb = 2 * b;
+    double cc = 3 * c;
+
+    double n = aa + bb + cc;
+
+    //////////////
+
+    dp[a][b][c] = 0;
+
+    if (n >= 3) {
+      dp[a][b][c] += (cc / n) * (2 / (n - 1)) * (1 / (n - 2))        * (get(a + 0, b + 0, c - 1) + 1 + 0);
+
+      dp[a][b][c] += (cc / n) * (2 / (n - 1)) * (aa / (n - 2))       * (get(a + 0, b + 0, c - 1) + 1 + 1);
+      dp[a][b][c] += (cc / n) * (2 / (n - 1)) * (bb / (n - 2))       * (get(a + 2, b - 1, c - 1) + 1 + 0);
+      dp[a][b][c] += (cc / n) * (2 / (n - 1)) * ((cc - 3) / (n - 2)) * (get(a + 1, b + 1, c - 2) + 1 + 0);
+    }
+
+    if (n >= 2) {
+      dp[a][b][c] += (cc / n) * (aa / (n - 1))                       * (get(a - 1, b + 1, c - 1) + 1 + 1);
+      dp[a][b][c] += (cc / n) * (bb / (n - 1))                       * (get(a + 1, b + 0, c - 1) + 1 + 0);
+      dp[a][b][c] += (cc / n) * ((cc - 3) / (n - 1))                 * (get(a + 0, b + 2, c - 2) + 1 + 0);
+    }
+
+    //////////////
+
+    if (n >= 2) {
+      dp[a][b][c] += (bb / n) * (1 / (n - 1))                        * (get(a + 0, b - 1, c + 0) + 1 + 0);
+
+      dp[a][b][c] += (bb / n) * (aa / (n - 1))                       * (get(a + 0, b - 1, c + 0) + 1 + 1);
+      dp[a][b][c] += (bb / n) * ((bb - 2) / (n - 1))                 * (get(a + 2, b - 2, c + 0) + 1 + 0);
+      dp[a][b][c] += (bb / n) * (cc / (n - 1))                       * (get(a + 1, b + 0, c - 1) + 1 + 0);
+    }
+
+    //////////////
+
+    dp[a][b][c] += (aa / n)                                          * (get(a - 1, b + 0, c + 0) + 1);
+
+  }
+}
+