Submission #66099900

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Source Code Expand

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#define ll long long
#define ld long double
#define int long long
#define nl "\n"
#define oo 1e9 + 1
#define OO 1e18 + 1
#define sp ' '
#define sz(x) (int)(x.size())
#define MOD 1000000007
#define fixed(n) fixed << setprecision(n)
#define sub_mod(a, b, m) ((((a) % m) - ((b) % m) + m) % m)
#define add_mod(a, b, m) ((((a) % m) + ((b) % m)) % m)
#define mult_mod(a, b, m) ((((a) % m) * ((b) % m)) % m)
#define EPS 1e-9
#define PI acos(-1)
using namespace __gnu_pbds;
using namespace std;

int n, m, mx_val = 0;
vector<vector<int>> a;
vector<vector<bool>> vis;
void rec(int i = 0, int j = 0, int cur_xor = 0)
{
    if (i == n)
    {
        mx_val = max(mx_val, cur_xor);
        return;
    }
    if (j == m)
    {
        rec(i + 1, 0, cur_xor);
        return;
    }
    if (vis[i][j])
    {
        rec(i, j + 1, cur_xor);
        return;
    }

    if (j + 1 < m && !vis[i][j + 1])
    {
        vis[i][j] = vis[i][j + 1] = true;
        rec(i, j + 2, cur_xor);
        vis[i][j] = vis[i][j + 1] = false;
    }
 
    if (i + 1 < n && !vis[i + 1][j])
    {
        vis[i][j] = vis[i + 1][j] = true;
        rec(i, j + 1, cur_xor);
        vis[i][j] = vis[i + 1][j] = false;
    }
    

    rec(i, j + 1, cur_xor ^ a[i][j]);
}
void solve()
{
    cin >> n >> m;
    a.resize(n, vector<int>(m));
    vis.resize(n, vector<bool>(m, false));
    for (int i = 0; i < n; i++)
    {
        for (int j = 0; j < m; j++)
        {
            cin >> a[i][j];
        }
    }
    rec(0, 0, 0);
    cout << mx_val << nl;
}
signed main(void)
{
    ios_base::sync_with_stdio(false), cin.tie(nullptr), cout.tie(nullptr);
    int tc = 1;
    //cin >> tc;
    while (tc--)
    {
        solve();
    }
    return 0;
}

Submission Info

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