Grid Challenge Discussions | Algorithms | HackerRank
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Grid Challenge

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598 Discussions

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  • CSE_B_22B0101072
     + 0 comments

    It's NOT square matrix. Problem Description is Bad

  • mh00062
     + 0 comments
    def gridChallenge(grid):
    grid = [sorted(s) for s in grid]   
     
    for c in range(len(grid[0])):
        c_str = [row[c] for row in grid]
        
        for i in range(1, len(c_str)):
            if c_str[i-1] > c_str[i]:
                return "NO"
            
    return "YES"

  • alban_tyrex
     + 0 comments

    Here is my c++ solution, you can watch the explanation here : https://youtu.be/GPB-dpsvQ8Y

    string gridChallenge(vector<string> grid) {
    for(int i = 0; i < grid.size(); i++) sort(grid[i].begin(), grid[i].end());
    for(int col = 0; col < grid.size(); col++){
       for(int row = 1; row < grid.size(); row++)
            if(grid[row][col] < grid[row-1][col]) return "NO";
    }
    return "YES";
}

  • emhhacker
     + 0 comments

    My Java solution with o(r * c log c) time complexity and o(r) space:

    public static String gridChallenge(List<String> grid) {
        if(grid.size() == 1) return "YES"; //no cols to check
        
        // 1. sort rows alphabetically ascending
        List<String> sortedGrid = new ArrayList<>();
        for(String row : grid){
            char[] chars = row.toCharArray();
            Arrays.sort(chars);
            sortedGrid.add(new String(chars));
        }
        
        // 2. check cols for alphabetically ascending order from top to bottom
        for(int col = 0; col < grid.get(0).length(); col++){
            for(int row = 1; row < grid.size(); row++){
                String currRow = sortedGrid.get(row);
                String prevRow = sortedGrid.get(row - 1);
                //check if col is in order
                if(currRow.charAt(col) < prevRow.charAt(col)) return "NO";
            }
        }
        return "YES";
    }

  • ahmet_alp77
     + 0 comments

    Java //O(n*n)

    public static String gridChallenge(List<String> grid) {
        int n = grid.size();
        int m = grid.get(0).length();
        char[][] matrix= new char[n][m];
        for(int i=0; i < n; ++i) {
                matrix[i] = grid.get(i).toCharArray();
                Arrays.sort(matrix[i]);
        }
        for(int j=0; j < m; ++j) {
                for(int i=1; i < n; ++i) {
                        if (matrix[i][j] < matrix[i-1][j]) {
                                return "NO";
                        }
                }        
        }
        return "YES";
}