hdu 4627 The Unsolvable Problem（暴力的搜索）

 1 #pragma comment(linker, "/STACK:1024000000,1024000000")
 2 #include<iostream>
 3 #include<cstdio>
 4 #include<cstring>
 5 #include<cmath>
 6 #include<math.h>
 7 #include<algorithm>
 8 #include<queue>
 9 #include<set>
10 #include<bitset>
11 #include<map>
12 #include<vector>
13 #include<stdlib.h>
14 using namespace std;
15 #define ll long long
16 #define eps 1e-10
17 #define MOD 1000000007
18 #define N 1000000
19 #define inf 1e12
20 ll n;
21 ll gcd(ll a,ll b){
22     return b==0?a:gcd(b,a%b);
23 }
24 ll lcm(ll a,ll b){
25     return a*b/gcd(a,b);
26 }
27 int main()
28 {
29     ll t;
30     scanf("%I64d",&t);
31     while(t--){
32         scanf("%I64d",&n);
33         
34         ll x=n/2;
35         ll r=gcd(x,n-x);
36         ll ans=x*(n-x)/r;
37         while(r!=1 && x>0){
38             x--;
39             r=gcd(x,n-x);
40             ans=max(ans,x*(n-x)/r);
41         }
42         printf("%I64d\n",ans);
43     }
44     return 0;
45 }