c++ - 3和最接近，带有错误: expected unqualified-id before string constant

Question

我检查了所有的半逗号，所以应该不成问题，有人可以通过Leetcode解决方案来帮助我吗？

    class Solution {
    public:
    int threeSumClosest(vector<int>& nums, int target) {
        int res=INT_MAX;

        std::sort(nums.begin(), nums.end());

        for(int i = 0; i<nums.size(); i++){
            //create target minus nums
            int qminus = target-nums[i];
            int closest = INT_MAX;
            //hashtable[nums[i]]=minus;

            //
            int front = i+1;
            int back = nums.size()-1;

            while(front<back){
                int sum = nums[front]+nums[back];

                if(sum<qminus)  {front++;
                                closest = minus - sum;
                                res = min(closest, res);
                               }
                else if(sum>qminus) {back--;
                                    closest = minus - sum;
                                    res = min(closest,res);
                                   }
                else res=0;
            }
            while(front<back && nums[i+1]==nums[i]) i++;
        }
        return res;

};

我在字符串常量前收到一个缺少unqualid-id的错误，有人可以帮我解决这个错误，谢谢!

Answer 1

您缺少右括号，并且没有名为minus的变量:

class Solution {
  public:
  int threeSumClosest(vector<int>& nums, int target) {
    int res=INT_MAX;

    std::sort(nums.begin(), nums.end());

    for(int i = 0; i<nums.size(); i++){
        //create target minus nums
        int qminus = target-nums[i];
        int closest = INT_MAX;
        //hashtable[nums[i]]=minus;

        //
        int front = i+1;
        int back = nums.size()-1;

        while(front<back){
            int sum = nums[front]+nums[back];

            if(sum<qminus)  {front++;
                            closest = qminus - sum; // did you mean qminus?
                            res = min(closest, res);
                           }
            else if(sum>qminus) {back--;
                                closest = qminus - sum; // did you mean qminus?
                                res = min(closest,res);
                               }
            else res=0;
        }
        while(front<back && nums[i+1]==nums[i]) i++;
    }
    return res;
  } // missing this bracket
};

Leetcode通常会为编译器错误指定行号，因此您下次应该可以使用该行号来更深入地了解问题。