Fox Ciel is playing a game with numbers now.
Ciel has n positive integers: x1, x2, ..., xn. She can do the following operation as many times as needed: select two different indexes iand j such that xi > xj hold, and then apply assignment xi = xi - xj. The goal is to make the sum of all numbers as small as possible.
Please help Ciel to find this minimal sum.
The first line contains an integer n (2 ≤ n ≤ 100). Then the second line contains n integers: x1, x2, ..., xn (1 ≤ xi ≤ 100).
Output a single integer — the required minimal sum.
2 1 2
2
3 2 4 6
6
2 12 18
12
5 45 12 27 30 18
15
In the first example the optimal way is to do the assignment: x2 = x2 - x1.
In the second example the optimal sequence of operations is: x3 = x3 - x2, x2 = x2 - x1.
有史以来第一次冲到第四题,有点思路,但是做不下去了。
提前把代码贴上吧
很简单的一道题,刚开始的想法是循环排序并作a[i]-=a[i-1]处理,提交后超时了
想到可以用a[i]%=a[i-1],但是这种情况要考虑到a[i]整除a[i-1]的情况,整除时另a[i]=a[i-1]
循环的条件是a[0]!=a[n-1];
代码如下:
#include <algorithm>
#include <iostream>
#include <string>
#include <vector>
#define maxn 200
using namespace std;
int a[maxn];
int main(void){
int n;
while(cin >> n){
for(int i=0; i<n; ++i){
cin >> a[i];
}
sort(a,a+n);
while(a[n-1] != a[0]){
for(int i=n-1; i>0; --i)
if(a[i]%a[i-1] == 0)
a[i] = a[i-1];
else a[i] %= a[i-1];
sort(a,a+n);
}
int sum = 0;
for(int i=0; i<n; ++i)
sum += a[i];
cout << sum << endl;
}
return 0;
}