Leetcode-5008 Fixed Point(不动点)

没啥好说的

#define _for(i,a,b) for(int i = (a);i < b;i ++)
class Solution
{
    public:
        int fixedPoint(vector<int>& A)
        {
            _for(i,0,A.size())
                if(i==A[i])
                    return i;
            return -1;
        }
};