3295 questions about algorithms in chapter 9 and chapter 9

3295 questions about algorithms in chapter 9 and chapter 9
Time Limit: 1 s space limit: 1000 KB title level: GoldQuestionView running resultsDescriptionDescription

There are n numbers (n is an odd number), n-1 numbers are paired in pairs, and one number is placed on a single order to find this number. Requires the time complexity of O (n) and the space complexity of O (1 ).

Input description Input Description

Enter n in the first line. n is an odd number greater than or equal to 1.

The second row contains n integers.

Output description Output Description

Number of orders output

Sample Input Sample Input

3

1 7 1

Sample output Sample Output

7

Data range and prompt Data Size & Hint

1 <= n <= 4000001 n is an odd number

CATEGORY tag Tags click here to expand

For any x,

Has the following properties:

X ^ y = x;

 1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<cmath> 5 #define lli long long int  6 using namespace std; 7 int main() 8 {     9     int n;10     cin>>n;11     n--;12     int now,x;13     cin>>now;14     while(n--)15     {16         scanf("%d",&x);17         now^=x;18     }19     cout<<now;20     return 0;21 }