HackR_Java_Code/friends_circle at master · sumitgupta1312/HackR_Java_Code · GitHub

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    /*
     * Complete the friendCircles function below.
     */
    static int friendCircles(String[] friends) {
        int len = friends.length;
        char[][] matrix = new char[len][len];
        for (int i = 0; i < len; i++) {
            matrix[i] = friends[i].toCharArray();
        }
        int n = matrix.length;
        if (n == 1) {
            return 1;
        }

        boolean[] assigned = new boolean[n];
        for (int i = 0; i < n; i++) {
            assigned[i] = false;
        }
        int circles = 0;

        for (int i = 0; i < n; i++) {
            if (assigned[i]) continue;
            assigned[i] = true;
            for (int j = 0; j < matrix.length; j++) {
                if (assigned[j]) continue;
                if (i == j) continue;
                if (matrix[i][j] == 'Y') {
                    assigned[j] = true;
                    updateInPlace(matrix, assigned, j);
                }
            }
            circles++;
        }
        return circles;
    }

    private static void updateInPlace(char[][] matrix, boolean[] assigned, int i) {
        for (int j = 0; j < matrix.length; j++) {
            if (assigned[j]) continue;
            if (i == j) continue;
            if (matrix[i][j] == 'Y') {
                assigned[j] = true;
                updateInPlace(matrix, assigned, j);
            }
        }
    }