java - 查找最大元素的索引

Question

我无法获取找到最大元素的索引。我知道数组中的元素可以通过 X[r] 访问，其中 r 是索引，这就是我在这里所做的，但我似乎无法仅获取索引。

代码:

public class Max {

public static void main(String[] args) {
    int[] B = {-1, 2, 6, 3, 9, 2, -3, -2, 11, 5, 7};
    System.out.println("max = " + maxArrayIndex(B, 0, B.length-1));
}

static int maxArrayIndex(int[] X, int p, int r) {
    int q = 0;
    if(p < r) {
       q = (p + r)/2;
       int maxLeft = maxArrayIndex(X, p, q);
       int maxRight = maxArrayIndex(X, q+1, r);
       int maxFinal = max(maxLeft, maxRight);
       return maxFinal;
      }
      return X[r];
   }

   static int max(int p , int r) {
       int maxIndex = 0;
       if(p > r) {
          maxIndex = p;
       } else {
           maxIndex = r;
       }
       return maxIndex;
     }
}

Answer 1

public class Max {
    public static void main(String[] args) {
        int[] B = {-1, 2, 6, 3, 9, 2, -3, -2, 11, 5, 7};
        System.out.println("max = " + maxArrayIndex(B, 0, B.length - 1));
    }

    static int maxArrayIndex(int[] X, int p, int r) {
        int q = 0;
        if (p < r) {
            q = (p + r) / 2;
            int maxLeft = maxArrayIndex(X, p, q);
            int maxRight = maxArrayIndex(X, q + 1, r);
            int maxFinal = max(X, maxLeft, maxRight);
            return maxFinal;
        }
        // Changed from X[r] to r. This will return the index instead of the element.
        return r;
    }

    // Added X parameter.
    static int max(int[] X, int p, int r) {
        int maxIndex = 0;

        // Changed to compare the elements of the indexes,
        // instead of comparing the indexes themselves.
        if (X[p] > X[r]) {
            maxIndex = p;
        } else {
            maxIndex = r;
        }
        return maxIndex;
    }
}

建议的替代方案:

static int maxArrayIndex(int[] X, int p, int r) {
    int currentMaxIndex = 0;
    for (int i = 0; i < X.length; i++) {
        if(X[i] > X[currentMaxIndex]){
            currentMaxIndex = i;
        }
    }
    return currentMaxIndex;
}