C++ :

#pragma comment(linker, "/STACK:102400000,102400000")
#include <map>
#include <set>
#include <stack>
#include <queue>
#include <cmath>
#include <string>
#include <vector>
#include <cstdio>
#include <cctype>
#include <cstring>
#include <sstream>
#include <cstdlib>
#include <iostream>
#include <algorithm>
#define MOD 1e9+7
#define lson l,mid,root<<1
#define rson mid+1,r,root<<1|1
#define DBN1(a)           cerr<<#a<<"="<<(a)<<"\n"
#define DBN2(a,b)         cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<"\n"
#define DBN3(a,b,c)       cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<", "<<#c<<"="<<(c)<<"\n"
#define DBN4(a,b,c,d)     cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<", "<<#c<<"="<<(c)<<", "<<#d<<"="<<(d)<<"\n"
#define DBN5(a,b,c,d,e)   cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<", "<<#c<<"="<<(c)<<", "<<#d<<"="<<(d)<<", "<<#e<<"="<<(e)<<"\n"
#define DBN6(a,b,c,d,e,f) cerr<<#a<<"="<<(a)<<", "<<#b<<"="<<(b)<<", "<<#c<<"="<<(c)<<", "<<#d<<"="<<(d)<<", "<<#e<<"="<<(e)<<", "<<#f<<"="<<(f)<<"\n"
using namespace std;
typedef long long ll;
const int maxn=100+5;
const int INF=0x3f3f3f3f;
const double PI=acos(-1.0);
template<typename T>
inline T read(T&x){
    x=0;int _f=0;char ch=getchar();
    while(ch<'0'||ch>'9')_f|=(ch=='-'),ch=getchar();
    while(ch>='0'&&ch<='9')x=x*10+ch-'0',ch=getchar();
    return x=_f?-x:x;
}
struct Edge{
    int from,to,cap,flow,cost;
    Edge(){}
    Edge(int f,int t,int c,int fl,int co):from(f),to(t),cap(c),flow(fl),cost(co){}
};
struct MCMF{
    int n,m,s,t,k;
    vector<Edge> edges;
    vector<int> G[maxn];
    bool inq[maxn];
    int d[maxn];
    int p[maxn];
    int a[maxn];

    void init(int n,int s,int t){
        this->n=n, this->s=s, this->t=t;
        edges.clear();
        for(int i=0;i<=n;++i) G[i].clear();
    }

    void AddEdge(int from,int to,int cap,int cost){
        edges.push_back(Edge(from,to,cap,0,cost));
        edges.push_back(Edge(to,from,0,0,-cost));
        m=edges.size();
        G[from].push_back(m-2);
        G[to].push_back(m-1);
    }

    bool SPFA(int &flow,int &cost){
        for(int i=0;i<n;++i) d[i]=INF;
        queue<int> Q;
        memset(inq,0,sizeof(inq));
        d[s]=0, Q.push(s), a[s]=INF, p[s]=0, inq[s]=true;
        while(!Q.empty()){
            int u=Q.front(); Q.pop();
            inq[u]=false;
            for(int i=0;i<G[u].size();++i){
                Edge &e=edges[G[u][i]];
                if(e.cap>e.flow && d[e.to]>d[u]+e.cost){
                    d[e.to]=d[u]+e.cost;
                    p[e.to]=G[u][i];
                    a[e.to]=min(a[u],e.cap-e.flow);
                    if(!inq[e.to]){ Q.push(e.to); inq[e.to]=true; }
                }
            }
        }
        if(d[t]==INF) return false;
        flow+=a[t];
        int u=t;
        while(u!=s){
            edges[p[u]].flow+=a[t];
            edges[p[u]^1].flow-=a[t];
            cost+=a[t]*edges[p[u]].cost;
            u=edges[p[u]].from;
        }
        return true;
    }

    int solve(){
        int flow=0,cost=0;
        while(SPFA(flow,cost));
        return cost;
    }
}MM;
int n,sum=0;
int a[maxn];
int main(){
    read(n);
    for (int i=1;i<=n;i++){
        read(a[i]);
        sum+=a[i];
    }
    sum/=n;
    MM.init(n+2,0,n+1);
    for (int i=1;i<=n;i++){
        MM.AddEdge(0,i,a[i],0);
        MM.AddEdge(i,n+1,sum,0);
        if (i!=n) MM.AddEdge(i,i+1,INF,1);
        if (i!=1) MM.AddEdge(i,i-1,INF,1);
    }
    MM.AddEdge(1,n,INF,1);
    MM.AddEdge(n,1,INF,1);
    printf("%d\n",MM.solve());
    return 0;
}