193B - Xor - CodeForces Solution

#include<bits/stdc++.h>
#define LL long long
#define DB double
#define MOD 1000000007
#define ls(x) x << 1
#define rs(x) x << 1 | 1
#define lowbit(x) x & (-x)
#define PII pair<int, int>
#define MP make_pair
#define VI vector<int>
#define VII vector<int>::iterator
#define EB emplace_back
#define SI set<int>
#define SII set<int>::iterator
#define QI queue<int>
using namespace std;
template<typename T> void chkmn(T &a, const T &b) { (a > b) && (a = b); }
template<typename T> void chkmx(T &a, const T &b) { (a < b) && (a = b); }
int inc(const int &a, const int &b) { return a + b >= MOD ? a + b - MOD : a + b; }
int dec(const int &a, const int &b) { return a - b < 0 ? a - b + MOD : a - b; }
int mul(const int &a, const int &b) { return 1LL * a * b % MOD; }
void Inc(int &a, const int &b) { ((a += b) >= MOD) && (a -= MOD); }
void Dec(int &a, const int &b) { ((a -= b) < 0) && (a += MOD); }
void Mul(int &a, const int &b) { a = 1LL * a * b % MOD; }
void Sqr(int &a) { a = 1LL * a * a % MOD; }
int qwqmi(int x, int k = MOD - 2)
{
    int res = 1;
    while(k)
    {
        if(k & 1) Mul(res, x);
        Sqr(x), k >>= 1;
    }
    return res;
}
// int f[35][2];
const LL INF = 1e18;
int n, m, r;
int a[35], b[35], k[35], p[35];
int w[35], g[35][35];
LL ans;
void dfs(int x, int op)
{
    // printf("now : ");
    // for(int i = 1; i <= n; ++i)
    //     printf("%d ", w[i]);
    // puts("");

    if((m - x + 1 + 1 ) & 1)
    {
        LL res = 0;
        for(int i = 1; i <= n; ++i)
            res += 1LL * w[i] * k[i];
        chkmx(ans, res);
    }
    if(x == m + 1) return;
    if(op == 0)
    {
        for(int i = 1; i <= n; ++i) g[x][i] = w[i];
        for(int i = 1; i <= n; ++i) w[i] = g[x][p[i]] + r;
        dfs(x + 1, 0);
        for(int i = 1; i <= n; ++i) w[i] = g[x][i];
        for(int i = 1; i <= n; ++i) w[i] ^= b[i];
        dfs(x + 1, 1);
        for(int i = 1; i <= n; ++i) w[i] = g[x][i];
    }
    if(op == 1)
    {
        for(int i = 1; i <= n; ++i) g[x][i] = w[i];
        for(int i = 1; i <= n; ++i) w[i] = g[x][p[i]] + r;
        dfs(x + 1, 0);
        for(int i = 1; i <= n; ++i) w[i] = g[x][i];
    }
}
int main()
{
    // f[1][0] = f[1][1] = 1;
    // for(int i = 2; i <= 30; ++i)
    // {
    //     f[i][0] = f[i - 1][0] + f[i - 1][1];
    //     f[i][1] = f[i - 1][0];
    // }
    // printf("%d\n", f[30][0] + f[30][1]);
    scanf("%d %d %d", &n, &m, &r);
    for(int i = 1; i <= n; ++i) scanf("%d", &a[i]), w[i] = a[i];
    for(int i = 1; i <= n; ++i) scanf("%d", &b[i]);
    for(int i = 1; i <= n; ++i) scanf("%d", &k[i]);
    for(int i = 1; i <= n; ++i) scanf("%d", &p[i]);
    ans = -INF;
    dfs(1, 0);
    printf("%lld\n", ans);
    return 0;
}