solve issue llipio#56 find minimum number of coins

solutions/56.js

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+// coin denomination problem
+
+const solution = (arr, total) => {
+  if (total === 0) {
+    return 0;
+  }
+
+  // set minimum number of coins to the total divided by smallest denomination
+  let min = Math.floor(total / Math.min(...arr));
+  arr.forEach((denom) => {
+    if (total - denom >= 0) {
+      min = Math.min(1 + solution(arr, total - denom), min);
+    }  
+  });
+  return min;
+};
+
+module.exports = {
+    solution
+};

test/56.js

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+const expect = require('chai').expect;
+const solution = require('../solutions/56.js').solution;
+// solution = require('../yourSolution').solution;
+
+describe('return smallest number of coins required to return the change', () => {
+  it('simplest case [1],total=1', () => {
+    expect(solution([1,2],2)).to.equal(1);
+  });
+  it('simple case [1,2],total=2', () => {
+    expect(solution([1,2],2)).to.equal(1);
+  });
+  it('simple case [1,2], total=4', () => {
+    expect(solution([1,2],4)).to.equal(2);
+  });
+  it('hard case [2,3,6,7], total=12', () => {
+    expect(solution([2,3,6,7],12)).to.equal(2);
+  });
+});
+