指向空指针的引用绑定

Question

class Solution {
public:
    int findMaxConsecutiveOnes(vector<int>& nums) {
        
        vector<int> cons;
        int count=0;
        int len=nums.size();
        
        if(nums.empty())
        {
            return 0;
        }
        else
        {   
              int i=0;
              while(i<len)
             {
                  if(nums[i]==1)
                {
                    count++;
                }
                else
               {
                  cons.push_back(count);
                  count=0;
                }
              i++;
              }
            int val=*max_element(cons.begin(),cons.end());
            return val;
        }
        
    }
};

为什么我会得到上面的错误。

Line 788: Char 16: runtime error: reference binding to null pointer of type 'int' (stl_iterator.h)
SUMMARY: UndefinedBehaviorSanitizer: undefined-behavior /usr/bin/../lib/gcc/x86_64-linux-gnu/8/../../../../include/c++/8/bits/stl_iterator.h:797:16

Answer 1

这就是问题所在

int val=*max_element(cons.begin(),cons.end());

添加此条件以检查cons是否不为空

int val;
     if(cons.size()!=0)
           val=*max_element(cons.begin(),cons.end());