Bag of Tokens

arraytwo pointersgreedy

Problem Statement

You start with an initial power of power , an initial score of 0 , and a bag of tokens given as an integer array tokens , where each tokens[i] denotes the value of token _i .

Your goal is to maximize the total score by strategically playing these tokens. In one move, you can play an unplayed token in one of the two ways (but not both for the same token):

Face-up : If your current power is at least tokens[i] , you may play token _i , losing tokens[i] power and gaining 1 score.

Face-down : If your current score is at least 1 , you may play token _i , gaining tokens[i] power and losing 1 score.

Return the maximum possible score you can achieve after playing any number of tokens .

Examples

Example 1

Input: tokens = [100], power = 50
Output: 0 
 Explanation : Since your score is 0 initially, you cannot play the token face-down. You also cannot play it face-up since your power ( 50 ) is less than tokens[0]  ( 100 ).

Example 2

Input: tokens = [200,100], power = 150
Output: 1
Play token _1 ( 100 ) face-up, reducing your power to  50 and increasing your score to  1 . 
 There is no need to play token _0 , since you cannot play it face-up to add to your score. The maximum score achievable is 1 .

Example 3

Input: tokens = [100,200,300,400], power = 200
Output: 2
Play the tokens in this order to get a score of 2 : 
 
 Play token _0 ( 100 ) face-up, reducing power to 100 and increasing score to 1 . 
 Play token _3 ( 400 ) face-down, increasing power to 500 and reducing score to 0 . 
 Play token _1 ( 200 ) face-up, reducing power to 300 and increasing score to 1 . 
 Play token _2 ( 300 ) face-up, reducing power to 0 and increasing score to 2 . 
 
 The maximum score achievable is 2 .

Constraints

0 <= tokens.length <= 1000

0 <= tokens[i], power < 10 ^4

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Medium

Difficulty

Topic Info

ModuleDSA

CategoryArray

Sub-topicTwo Pointers