#include<iostream>
#include<unordered_set>
#include<vector>
using namespace std;
class Solution {
public:
bool containsDuplicate(vector<int>& nums) {
unordered_set<int> s; //会显示 "未定义标识符unordered_set"
for (int x: nums) { //这里会显示"应输入; "
if (s.find(x) != s.end()) {
return true;
}
s.insert(x);
}
return false;
}
};
...
...