Submission #66134997

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;

int n, m;
vector<vector<int>> grid;
int max_xor = 0;

void dfs(int i, int j, int current_xor, vector<vector<bool>>& visited) {
    // Mark current cell as visited
    visited[i][j] = true;
    
    // Update current XOR with current cell value
    current_xor ^= grid[i][j];
    
    // Update global maximum XOR
    if (current_xor > max_xor) {
        max_xor = current_xor;
    }
    
    // Directions: up, down, left, right
    int dirs[4][2] = {{1, 0}, {0, 1}};
    
    // Explore all 4 possible directions
    for (auto& dir : dirs) {
        int ni = i + dir[0];
        int nj = j + dir[1];
        
        // Check if next cell is within bounds and not visited
        if (ni >= 0 && ni < n && nj >= 0 && nj < m && !visited[ni][nj]) {
            dfs(ni, nj, current_xor, visited);
        }
    }
    
    // Backtrack: unmark current cell
    visited[i][j] = false;
}

int main() {
    // Read grid dimensions
    cin >> n >> m;
    
    // Read grid values
    grid.resize(n, vector<int>(m));
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            cin >> grid[i][j];
        }
    }
    
    // Initialize visited matrix
    vector<vector<bool>> visited(n, vector<bool>(m, false));
    
    // Perform DFS from each cell as starting point
    for (int i = 0; i < n; i++) {
        for (int j = 0; j < m; j++) {
            dfs(i, j, 0, visited);
        }
    }
    
    // Output the maximum XOR found
    cout << max_xor << endl;
    
    return 0;
}

Submission Info

Judge Result