217. 存在重复元素

class Solution {
public:
    bool containsDuplicate(vector<int>& nums) {
        if(!nums.size()) return false;
        sort(nums.begin(),nums.end());
        
        vector<int>::iterator b=nums.begin();
        
        int val=*(b++);
        
        while(b!=nums.end()){
            cout<<val<<" "<<*b<<endl;
            if(val==*b)
                return true;
            else
                val=*b;
            ++b;
        }
        return false;
    }
};