```//0062 数组中出现一次的数字

//还有O(n)的一会补
class Solution {
public:
int findNumberAppearingOnce(vector[HTML_REMOVED]& nums) {
map[HTML_REMOVED]buff;
for (auto t:nums) {
buff[t]++;
}
map[HTML_REMOVED]::iterator i = buff.begin();

    for (; i != buff.end(); ++i) {
        if (i -> second == 1)
            return i -> first;
    }
}

};
```