Description

Submission

class Solution {
    using pii = pair<int, int>;
public:
    vector<vector<int>> colorBorder(vector<vector<int>>& grid, int row, int col, int color) {
        int m = grid.size(), n = grid[0].size();
        queue<pii> q;
        q.push({row, col});
        int connectedColor = grid[row][col];
        const vector<int> dirs {-1, 0, 1, 0, -1};
        vector<vector<bool>> visited(m, vector<bool>(n, false));
        auto rets = grid;

        while(!q.empty()) {
            auto [x, y] = q.front();
            q.pop();

            if(visited[x][y]) continue;
            visited[x][y] = true;

            for(int i = 0; i < 4; ++i) {
                int nextX = x + dirs[i], nextY = y + dirs[i+1];

                if(nextX < 0 || nextX >= m || nextY < 0 || nextY >= n) {
                    rets[x][y] = color;
                    continue;
                } 
                if(grid[nextX][nextY] != connectedColor) {
                    visited[nextX][nextY] = true;
                    rets[x][y] = color;
                    continue;
                }

                q.push({nextX, nextY});
            }
        }

        return rets;
        
    }
};

// [[1,2,1,2,1,2],
//  [2,2,2,2,1,2],
//  [1,2,2,2,1,2]]

//  [[1,1,1,1,1,2],
//   [1,2,1,1,1,2],
//   [1,1,1,1,1,2]]