HDU 5798 Stabilization

方法太厉害了....看了官方题解的做法....然后...想了很久很久才知道他想表达什么....

#pragma comment(linker, "/STACK:1024000000,1024000000")
#include<cstdio>
#include<cstring>
#include<cmath>
#include<algorithm>
#include<vector>
#include<map>
#include<set>
#include<queue>
#include<stack>
#include<iostream>
using namespace std;
typedef long long LL;
const double pi=acos(-1.0),eps=1e-8;
void File()
{
    freopen("D:\\in.txt","r",stdin);
    freopen("D:\\out.txt","w",stdout);
}
inline int read()
{
    char c = getchar();  while(!isdigit(c)) c = getchar();
    int x = 0;
    while(isdigit(c)) { x = x * 10 + c - '0'; c = getchar(); }
    return x;
}

int T,n;
LL a[100010],f[25][25],ans1,ans2;
int d[25];

void dfs(int s,LL b, LL sum)
{
    if(s==-1)
    {
        if(sum<ans1) ans1=sum,ans2=b;
        else if(sum==ans1) ans2=min(ans2,b);
        return;
    }

    for(d[s]=0;d[s]<=1;d[s]++)
    {
        LL t=sum; t=t+f[s][s];
        for(int j=19;j>s;j--)
        {
            if((d[j]+d[s])%2==0) t=t+f[j][s];
            else t=t-f[j][s];
        }
        dfs(s-1,b|(d[s]*(1<<s)),t);
    }
}

int main()
{
    scanf("%d",&T); while(T--)
    {
        scanf("%d",&n);
        for(int i=1;i<=n;i++) scanf("%lld",&a[i]);
        memset(f,0,sizeof f); ans1=0, ans2=0;
        for(int i=2;i<=n;i++)
        {
            ans1=ans1+abs(a[i]-a[i-1]);
            if(a[i]==a[i-1]) continue;
            int h=-1;
            for(int j=19;j>=0;j--)
            {
                int x1=0,x2=0;
                if(a[i]&(1<<j)) x1=1; if(a[i-1]&(1<<j)) x2=1;
                if(x1==x2) continue; h=j; break;
            }
            int x=max(a[i],a[i-1]),y=min(a[i],a[i-1]);
            for(int j=h;j>=0;j--)
            {
                int x1=0,x2=0;
                if(x&(1<<j)) x1=1; if(y&(1<<j)) x2=1;
                f[h][j]=f[h][j]+(x1-x2)*(1<<j);
            }
        }
        dfs(19,0,0);
        printf("%lld %lld\n",ans2,ans1);
    }
    return 0;
}