201612-1 中间数

 1 #include <iostream>
 2 #include <algorithm>
 3 using namespace std;
 4 
 5 bool com(int a[],int n,int x)
 6 {
 7     int l = 0,r = 0;
 8     for(int i = 0;i < n/2;i ++)
 9         if(a[i] < x)    l++;
10     for(int i = n-1;i > n/2;i --)
11         if(a[i] > x)    r++;
12     if(l == r)
13         return true;
14     else
15         return false;
16 }
17 int main()
18 {
19     int n;
20     cin>>n;
21     int a[1010];
22     for(int i = 0; i < n; i ++)
23         cin>>a[i];
24     sort(a,a + n);
25     int res = a[n/2];
26     if(com(a,n,res))
27         cout<<res<<endl;
28     else
29         cout<<"-1"<<endl;
30     return 0;
31 }