An array of reverse

• Requirement: Reverse the contents of the array elements. ArrayReverse.java

arr {11.22.33.44.55.66} {66.55.44.33.22.11}
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Method 1: By finding a pattern reversal

• 【 答 案 】
• regular
  
  The 1.arr[0] 和 arr[5]swapping,22,33,44,55,11 {66}
  
  The 2.arr[1] 和 arr[4]swapping,55,33,44,22,11 {66}
  
  The 3.arr[2] 和 arr[3]swapping,55,44,33,22,11 {66}
  
  4. It’s a total swap3 times = arr.length / 2
  
  5. For each swap, the corresponding subscript isArr [I] and ARr [arr. Length-1-i]

	  int temp = 0;
      int len = arr.length; // Calculate the length of the array
      for( int i = 0; i < len / 2; i++) {
          temp = arr[len - 1 - i];/ / save
          arr[len - 1 - i] = arr[i];
          arr[i] = temp;
      }

      System.out.println("=== = flipped array ===");
      for(int i = 0; i < arr.length; i++) {
          System.out.print(arr[i] + "\t");/ / 66,55,44,33,22,11
      }
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Method 2: Use the reverse assignment mode arrayReverse02.java

• Train of thought
  
  1. Create a new arrayarr2, size,arr.length
  
  2. Reverse traversalarr, copy each element toarr2(sequential copy)
  
  3. It is recommended to add a loop variablej -> 0 -> 5

	 int[] arr2 = new int[arr.length];
      // Reverse arR
      for(int i = arr.length - 1, j = 0; i >= 0; i--, j++) {
          arr2[j] = arr[i];
      }
      {66, 55, 44,33, 22, 11}
      //5. Make arR point to arR2 data space, then there is no variable reference in arR original data space
      // Will be disposed of as garbage
      arr = arr2;
      System.out.println("==== Elements of ARR =====");
      //6. Output arR
      for(int i = 0; i < arr.length; i++) {
          System.out.print(arr[i] + "\t");
        }
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