Import java. util. treemap;

public class hw1 {
/**
* inverts an array of strings by returning a treemap that maps strings to the smallest index in the array that contains the string.
*
* @param a an array of strings
* @return a map that given a string returns the smallest index of the array that contains the string
* (or null if string is not in the array a).
*/
public static treemap invert(string[] a) {
//to do
return null;
}

/**
* computes the total number of occurrences of every string in an array.
*
* @param a an array of strings
* @return a map that given a string returns the number of occurrences of that string in the array
* (or null if string is not in the array a).
*/
public static treemap count(string[] a) {
// todo
return null;
}
}