upload solutions

E/Main.java

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+import java.io.*;
+import java.util.*;
+
+public class Main {
+
+  static class FastReader {
+    BufferedReader br;
+    StringTokenizer st;
+
+    public FastReader() {
+      br = new BufferedReader(new InputStreamReader(System.in));
+    }
+
+    String next() {
+      while (st == null || !st.hasMoreElements()) {
+        try {
+          st = new StringTokenizer(br.readLine());
+        } catch (Exception e) {
+          return null;
+        }
+      }
+      return st.nextToken();
+    }
+
+    int nextInt() {
+      return Integer.parseInt(next());
+    }
+
+    long nextLong() {
+      return Long.parseLong(next());
+    }
+  }
+
+  static int upperBound(long[] arr, long key) {
+    int low = 0, high = arr.length - 1;
+    int ans = arr.length;
+    while (low <= high) {
+      int mid = (low + high) >>> 1;
+      if (arr[mid] > key) {
+        ans = mid;
+        high = mid - 1;
+      } else {
+        low = mid + 1;
+      }
+    }
+    return ans;
+  }
+
+  static void add(long[] bit, int idx, long val) {
+    for (; idx < bit.length; idx += idx & -idx)
+      bit[idx] += val;
+  }
+
+  static long query(long[] bit, int idx) {
+    long sum = 0;
+    for (; idx > 0; idx -= idx & -idx)
+      sum += bit[idx];
+    return sum;
+  }
+
+  public static void main(String[] args) {
+    FastReader sc = new FastReader();
+    String firstToken = sc.next();
+    if (firstToken == null)
+      return;
+    int n = Integer.parseInt(firstToken);
+
+    long[] a = new long[n];
+    for (int i = 0; i < n; i++) {
+      a[i] = sc.nextLong();
+    }
+
+    long[] u = new long[n];
+    long[] v = new long[n];
+    long min_val = Long.MAX_VALUE;
+    long max_val = Long.MIN_VALUE;
+
+    for (int i = 0; i < n; i++) {
+      u[i] = a[i] - (i + 1);
+      v[i] = a[i] + (i + 1);
+      if (u[i] < min_val)
+        min_val = u[i];
+      if (v[i] < min_val)
+        min_val = v[i];
+      if (u[i] > max_val)
+        max_val = u[i];
+      if (v[i] > max_val)
+        max_val = v[i];
+    }
+
+    long[] sorted_u = u.clone();
+    Arrays.sort(sorted_u);
+    int u_unique = 1;
+    for (int i = 1; i < n; i++) {
+      if (sorted_u[i] != sorted_u[i - 1])
+        sorted_u[u_unique++] = sorted_u[i];
+    }
+    sorted_u = Arrays.copyOf(sorted_u, u_unique);
+
+    long[] sorted_v = v.clone();
+    Arrays.sort(sorted_v);
+    int v_unique = 1;
+    for (int i = 1; i < n; i++) {
+      if (sorted_v[i] != sorted_v[i - 1])
+        sorted_v[v_unique++] = sorted_v[i];
+    }
+    sorted_v = Arrays.copyOf(sorted_v, v_unique);
+
+    long[] bit_L_count = new long[u_unique + 1];
+    long[] bit_L_sum = new long[u_unique + 1];
+    long[] bit_R_count = new long[v_unique + 1];
+    long[] bit_R_sum = new long[v_unique + 1];
+
+    long total_S_L = 0;
+    long total_S_R = 0;
+
+    for (int i = 0; i < n; i++) {
+      int idx = Arrays.binarySearch(sorted_v, v[i]) + 1;
+      add(bit_R_count, idx, 1);
+      add(bit_R_sum, idx, v[i]);
+      total_S_R += v[i];
+    }
+
+    long ans = Long.MAX_VALUE;
+    int targetCount = (n + 1) / 2;
+
+    for (int p = 1; p <= n; p++) {
+      int idxU = Arrays.binarySearch(sorted_u, u[p - 1]) + 1;
+      add(bit_L_count, idxU, 1);
+      add(bit_L_sum, idxU, u[p - 1]);
+      total_S_L += u[p - 1];
+
+      int idxV = Arrays.binarySearch(sorted_v, v[p - 1]) + 1;
+      add(bit_R_count, idxV, -1);
+      add(bit_R_sum, idxV, -v[p - 1]);
+      total_S_R -= v[p - 1];
+
+      long low = min_val - 2L * n;
+      long high = max_val + 2L * n;
+      long x_med = high;
+
+      while (low <= high) {
+        long mid_val = low + ((high - low) >> 1);
+
+        int countL = (int) query(bit_L_count, upperBound(sorted_u, mid_val));
+        int countR = (int) query(bit_R_count, upperBound(sorted_v, mid_val + 2L * p));
+
+        if (countL + countR >= targetCount) {
+          x_med = mid_val;
+          high = mid_val - 1;
+        } else {
+          low = mid_val + 1;
+        }
+      }
+
+      long x = Math.max(x_med, Math.max(0L, n - 2L * p + 1L));
+
+      int iL = upperBound(sorted_u, x);
+      long cL = query(bit_L_count, iL);
+      long sL = query(bit_L_sum, iL);
+      long costL = (cL * x - sL) + ((total_S_L - sL) - (p - cL) * x);
+
+      long y = x + 2L * p;
+      int iR = upperBound(sorted_v, y);
+      long cR = query(bit_R_count, iR);
+      long sR = query(bit_R_sum, iR);
+      long costR = (cR * y - sR) + ((total_S_R - sR) - ((n - p) - cR) * y);
+
+      ans = Math.min(ans, costL + costR);
+    }
+
+    System.out.println(ans);
+  }
+}

E/test1.in

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+4
+1 1 2 3

E/test2.in

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+5
+4 5 7 2 2

E/test3.in

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+6
+4 5 6 5 4 3