题解 | #牛牛与木棍#

思路：找最终的木棍长度

#include <bits/stdc++.h>
using namespace std;
int n,a[55];

int findans(int num, int a)
{
    int cot=0,top=a,down=a;
    while (down < num)
    {
        if (top>=num && down<=num)
            break;
        cot++;
        top = top*2+1;
        down = down*2-1;
    }
    if (down > num)
        return -1;
    else
        return cot;
}

queue<int > ll;

int main()
{
    int res=-1, minn=1e9;
    scanf("%d",&n);
    for (int i=1; i<=n; i++){
        scanf("%d",&a[i]);
        minn = min(minn,a[i]);
    }
    ll.push(minn);
    int l;
    while (res == -1)
    {
        l = ll.front();
        ll.pop();
        res = 0;
        for (int i=1; i<=n; i++)
        {
            int tmp = findans(a[i],l);
            if (tmp == -1){
                res = -1;
                break;
            }
            else{
                res += tmp;
            }
        }
        if (l%2 == 0){
            ll.push(l/2);
        }
        else {
            ll.push((l+1)/2);
            ll.push((l-1)/2);
        }
    }
    printf("%d",res);
    return 0;
}