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

function gridChallenge(grid) {
    for (let i = 0; i < grid.length; i++) {
        grid[i] = sortString(grid[i]);
    }
    let answer = 'YES';
    for (let idr = 1; idr < grid.length; idr++) {
        for (let idc = 0; idc < grid[0].length; idc++) {
            if (grid[idr][idc] < grid[idr-1][idc]) {
                answer = 'NO';
                break;
            }
        }
    }
    return answer;
}

function sortString(str) {
    const ALPHABET_SIZE = 26;
    const charCount = Array(ALPHABET_SIZE).fill(0);
    const asciiStartLowercase = "a".charCodeAt(0);

    for (const char of str) {
        charCount[char.charCodeAt(0) - asciiStartLowercase]++;
    }

    let sortedStr = "";
    for (let i = 0; i < charCount.length; i++) {
        if (charCount[i] > 0) {
            sortedStr += String.fromCharCode(i + asciiStartLowercase).repeat(charCount[i]);
        }
    }
    return sortedStr;
}

function gridChallenge(grid) {
    // Write your code here
    const sortedGrid = grid.map(row => row.split('').sort().join(''))

    for(let col = 0; col < sortedGrid[0].length; col++){
        for(let row = 1; row < sortedGrid.length; row++){
            if(sortedGrid[row][col] < sortedGrid[row - 1][col]){
                return "NO"
            }
        }
    }

    return "YES"
}