你能快点告诉我这个伪代码是否有意义吗？

Question

我相信我的代码现在是万无一失的。我现在会写出伪代码。但我确实有一个问题。为什么DRJava要求我在if语句之外返回一些东西？正如你所看到我为前写的：“返回1;”只是因为它问。但它永远不会返回那个值。有人可以向我解释一下吗？

public class assignment1question2test {
  public static void main(String[] args) {

    int[] a = new int[50];
    int l = 0;
    int r = a.length;

    for(int i=0; i<r; i++) {
      a[i] = 1;
    }

    a[0] = 10;

    for (int i=0; i<r; i++) { 
      System.out.println(a[i]);
    }

    System.out.print(recursiveSearch(a,l,r));

  }

  public static int recursiveSearch (int[] a, int l, int r) {

    int third1 = (r-l)/3 + l;
    int third2 = third1*2 - l + 1;

      System.out.println("i will be checking compare from " + l + " to " + third1 + " and " + (third1 + 1) + " to " + third2);
      int compareResult = compare(a,l,third1,third1 + 1, third2);

      if(r-l == 1) {
      if (compareResult == 1) {
        return l;
      }
      else {
        return r;
      }
      }

      if (compareResult == 0) {
        return recursiveSearch(a,third2 + 1, r);
      }
      if (compareResult == 1) {
        return recursiveSearch(a,l,third1);
      }
      if (compareResult == -1) {
        return recursiveSearch(a,third1 + 1, third2);
      }
      return 1;

  }
  public static int compare(int[] a, int i, int j, int k, int l) {

    int count1 = 0;
    int count2 = 0;

    for(int g=i; g<=j; g++) {
      count1 = count1 + a[g];
    }

    for(int g=k; g<=l; g++) {
      count2 = count2 + a[g];
    }

        if (count1 == count2) {
          return 0;
        }
        if (count1 > count2) {
          return 1;
        }
        if (count1 < count2) {
          return -1;
        }  

        return 0;
}
}

更新的最终伪代码：

Algorithm: recursiveSearch (a,l,r)
Inputs: An array a, indices l and r which delimit the part of interest.
Output: The index that has the lead coin.
int third1 ← (r - l + 1)/3
int third2 ← third1*2 - l + 1
if (r-l = 0) then
    return l
int compareResult  ← compare(a,l,third1,third1 + 1,third2)
if (r-l  = 1) then
    if (compareResult = 1) then
        return l
    else 
        return r
if (compareResult = 0) then
    return recursiveSearch(a, third2 + 1, r)
if (compareResult = "1") then
    return recursiveSearch(a,l,third1)
if (compareResult = "-1") then
    return recursiveSearch(a,third1 + 1,third2)

Answer 1

您似乎在以下搜索中包含mid，无论哪一方更大。递归调用应该从搜索空间中排除mid。

此外，为了使比较有意义，要比较的两个组需要具有相同的大小。这将需要一些额外的奇数/偶数逻辑。