/*
In "the 100 game," two players take turns adding, to a running
total, any integer from 1..10. The player who first causes the running
total to reach or exceed 100 wins.
What if we change the game so that players cannot re-use integers?
For example, if two players might take turns drawing from a common pool of numbers
of 1..15 without replacement until they reach a total >= 100. This problem is
to write a program that determines which player would win with ideal play.
Write a procedure, "Boolean canIWin(int maxChoosableInteger, int desiredTotal)",
which returns true if the first player to move can force a win with optimal play.
Your priority should be programmer efficiency; don't focus on minimizing
either space or time complexity.
*/
Boolean canIWin(int maxChoosableInteger, int desiredTotal) {
// Implementation here. Write yours
}
Solution from here http://codeanytime.blogspot.com/2015/01/caniwin.html
//The catch is: when the largest number remaining is greater than the target remaining, the player is sure to win
//helper returns true if the CURRENT player can win
public boolean canIWin(int max, int target) {
List<Integer> candidates = new ArrayList<Integer>();
for (int i = 1; i <= max; i++){
candidates.add(i);
}
return helper(candidates, target);
}
public boolean helper(List<Integer> candidates, int target){
if (candidates.get(candidates.size()-1) >= target){
return true;
}
for (int i = 0; i < candidates.size(); i++){
int removed = candidates.remove(i);
if (!helper(candidates, target-removed)){
candidates.add(i, removed);
return true;
}
candidates.add(i, removed);
}
return false;
}