[BZOJ4827][Hnoi2017]礼物

#include <cstdio>
#include <algorithm>
using namespace std;
inline int readint(){
    int n = 0;
    char ch = getchar();
    while(ch < ‘0‘ || ch > ‘9‘) ch = getchar();
    while(ch <= ‘9‘ && ch >= ‘0‘){
        n = (n << 1) + (n << 3) + (ch & 15);
        ch = getchar();
    }
    return n;
}
typedef long long ll;
const int maxn = 1 << 18;
const ll P = 479 << 21 | 1, g = 3;
ll wn[20];
inline ll ksm(ll a, ll b, const ll &mod){
    ll s = 1;
    while(b){
        if(b & 1) s = s * a % mod;
        b >>= 1;
        a = a * a % mod;
    }
    return s;
}
void change(ll s[], int len){
    for(int i = 0, j = 0, k; i < len - 1; i++){
        if(i < j) swap(s[i], s[j]);
        k = len >> 1;
        while(j >= k){
            j -= k;
            k >>= 1;
        }
        j += k;
    }
}
void FNTT(ll s[], int len, int on){
    change(s, len);
    for(int id = 0, h = 2; h <= len; h <<= 1){
        id++;
        for(int j = 0; j < len; j += h){
            ll w = 1;
            for(int k = j; k < j + (h >> 1); k++){
                ll u = s[k] % P, t = w * s[k + (h >> 1)] % P;
                s[k] = (u + t) % P;
                s[k + (h >> 1)] = (u - t + P) % P;
                w = w * wn[id] % P;
            }
        }
    }
    if(on == -1){
        for(int i = 1; i < (len >> 1); i++) swap(s[i], s[len - i]);
        ll inv = ksm(len, P - 2, P);
        for(int i = 0; i < len; i++) s[i] = s[i] * inv % P;
    }
}
ll x[maxn], y[maxn], A[maxn], B[maxn];
int main(){
    for(int i = 1; i < 20; i++) wn[i] = ksm(3, (P ^ 1) >> i, P);
    int n, m;
    n = readint();
    m = readint();
    ll s1 = 0, s2 = 0;
    for(int i = 0; i < n; i++) x[i] = readint();
    for(int i = 0; i < n; i++) y[i] = readint();
    for(int i = 0; i < n; i++){
        s1 += x[i] * x[i] + y[i] * y[i];
        s2 += x[i] - y[i];
    }
    for(int i = 0; i < n; i++){
        A[i] = x[i];
        B[i] = y[n - i - 1];
    }
    int len = 1;
    while(len < (n << 1)) len <<= 1;
    FNTT(A, len, 1);
    FNTT(B, len, 1);
    for(int i = 0; i < len; i++) A[i] = A[i] * B[i] % P;
    FNTT(A, len, -1);
    ll mx = 0;
    for(int i = 0; i < n; i++) mx = max(mx, A[i] + A[i + n]);
    s1 -= mx << 1;
    ll dcz =  s2 / n;
    ll ans = s1 - 2LL * dcz * s2 + dcz * dcz * n;
    dcz++;
    ans = min(ans, s1 - 2LL * dcz * s2 + dcz * dcz * n);
    dcz -= 2;
    ans = min(ans, s1 - 2LL * dcz * s2 + dcz * dcz * n);
    printf("%lld\n", ans);
    return 0;
}