Add Pascal's Triangle based solution for Unique Paths problem.

src/algorithms/uncategorized/unique-paths/uniquePaths.js

@@ -0,0 +1,13 @@
+import pascalTriangle from '../../math/pascal-triangle/pascalTriangle';
+
+/**
+ * @param {number} width
+ * @param {number} height
+ * @return {number}
+ */
+export default function uniquePaths(width, height) {
+  const pascalLine = width + height - 2;
+  const pascalLinePosition = Math.min(width, height) - 1;
+
+  return pascalTriangle(pascalLine)[pascalLinePosition];
+}