Given various ways to score points, represented by an arbitrary array w, count how many ways you can add up to a score s. Raw

dynamic_programming_combinations.js

function waysToScore(awards, score) {

  var ways = new Array(score + 1).fill(0);

  // There's one way to score 0 points
  ways[0] = 1;

  // Loop through the awards
  for (var a = 0; a < awards.length; a++){
    // Loop through each integer from the award value up to the score
    for (var s = awards[a]; s <= score; s++){
      // Calculate what the score must have been prior to award
      let previousScore = ways[s - awards[a]];
      // Add each of the ways of getting previousScore to current ways
      ways[s] += previousScore;
    }
  }
  // return the score (or 0 if it is still undefined)
  return ways[score];
}

waysToScore([2, 3, 7, 8], 0);  // 1
waysToScore([2, 3, 7, 8], 1);  // 0
waysToScore([2, 3, 7, 8], 2);  // 1
waysToScore([2, 3, 7, 8], 3);  // 1
waysToScore([2, 3, 7, 8], 4);  // 1
waysToScore([2, 3, 7, 8], 5);  // 1
waysToScore([2, 3, 7, 8], 6);  // 2
waysToScore([2, 3, 7, 8], 7);  // 2
waysToScore([2, 3, 7, 8], 8);  // 3
waysToScore([2, 3, 7, 8], 9);  // 3
waysToScore([2, 3, 7, 8], 26); // 23