C++ :

#include <cstdio>
int main(){
    int n; if(scanf("%d",&n)!=1) return 0;
    int h[1005];
    for(int i=0;i<n;i++)scanf("%d",&h[i]);
    long long best=-1;
    // 枚举最终高度下界 L，所有山调到 [L, L+17]
    for(int L=-20;L<=100;L++){
        long long c=0;
        for(int i=0;i<n;i++){
            if(h[i]<L)c+=(long long)(L-h[i])*(L-h[i]);
            else if(h[i]>L+17)c+=(long long)(h[i]-L-17)*(h[i]-L-17);
        }
        if(best<0||c<best)best=c;
    }
    printf("%lld\n", best);
    return 0;
}