Question

我试图用分而治之的方法解决最大subArray和问题，但是发生了运行时错误（StackOverFlow），我不知道如何处理它，我认为这是由于我的递归调用而发生的。这是我的方法（错误发生在第一行递归行）：

class Solution {

    public int maxSubArray(int[] nums){
        int length = nums.length;
         int middle = length / 2;
         if(length == 1) {
             return nums[0];
         }

         int[] starting = Arrays.copyOfRange(nums, 0, middle+1);
         int[] ending = Arrays.copyOfRange(nums, middle +1, length);

         int left = maxSubArray(starting);
         int right = maxSubArray(ending);
         int crossing = computeCrossingSum(starting,ending);

         int result = Math.max(left,right);
         int finalResult = Math.max(result,crossing);

         return finalResult;
     }

     public int computeCrossingSum (int[] left, int[]right){

         int leftS =Integer.MIN_VALUE;
         int rightS =Integer.MIN_VALUE;
         int leftIndex;
         int rightIndex;

         int sumS = 0;
         for(int i = left.length -1 ; i>=0 ; i--) {
             sumS += left[i];
             if (sumS > leftS) {
                 leftS = sumS;
                 leftIndex = i;
             }
         }


         int sumA = 0;
         for(int i = 0 ; i< right.length ; i++){
             sumA+=right[i];
             if (sumA > rightS){
                 rightS = sumA;
                 leftIndex = i;
             }
         }

         int crossingSum = leftS+rightS;
         return crossingSum;
    }
}

Answer 1

递归调用中的middle + 1永远不允许数组大小为1，因此永远不会满足停止条件。删除+ 1

int[] starting = Arrays.copyOfRange(nums, 0, middle);
int[] ending = Arrays.copyOfRange(nums, middle, length);

StackOverFlow发生分而治之的问题：最大subArray

1 个答案: