README.md

An easy dynamic programming problem.

We define ans[i] as the fewest numbers that we can make up the amount i, and if can not, we define it as the value undefined, then we can enum every number that the array coins give, update the array ans, finally to check the value ans[amount].

The recursion is as below:

for (var i = 0, len = coins.length; i < len; i++) {
  var item = coins[i];
  for (var j = 0; j + item <= amount; j++) {
    if (ans[j] === undefined)
      continue;
    if (ans[j + item] === undefined)
      ans[j + item] = ans[j] + 1;
    else 
      ans[j + item] = Math.min(ans[j + item], ans[j] + 1);
  }
}