added matrixReshape

Author: mgable

matrixReshape.js

@@ -0,0 +1,28 @@
+/**
+ * @param {number[][]} nums
+ * @param {number} r
+ * @param {number} c
+ * @return {number[][]}
+ */
+var matrixReshape = function(nums, r, c) {
+  let flat = nums.reduce((acc, i) => {
+    acc = acc.concat(i); 
+    return acc}, [])
+
+  if (r * c !== flat.length){
+    return nums
+  }
+
+  let results = [],
+  index = 0;
+
+  for (let i = 1; i <= r; i++){
+    let row = []
+    for (let j = 1; j <= c; j++){
+      row.push(flat[index++])
+    }
+    results.push(row)
+  }
+
+  return results
+};