delete unused files

src/components/Preview/Counting.tsx

-import { useCountingSort } from '../../hooks/counting';
-import './Preview.css';
-
-interface props { list: number[] };
-
-
-function CountingPreview({ list }: props) {
-  const { items, highlight } = useCountingSort(list, 50);
-  return (
-    <div className="preview-box">
-      {items.map((height, index) =>
-      <div
-        style={{height: height*10}}
-        className={"item "+(index === highlight ? "highlight" : "")}
-      />)}
-    </div>
-  )
-};
-
-export default CountingPreview;
\ No newline at end of file

src/hooks/counting.ts

-import * as React from 'react';
-
-interface StepState {
-    list: number[],
-    index: number,
-    lastIndex: number,
-    counter: number,
-    numOfSwaps: number,
-    lastSwapIndex: number
-};
-function countingSortStep(state: StepState) : StepState {
-    const {list,index,lastIndex,counter,numOfSwaps,lastSwapIndex} = state;
-
-    if (numOfSwaps === list.length) {
-        return state;
-    }
-    if (index === lastIndex) {
-        return nextCount(state);
-    } else if (list[index] === counter) {
-        return moveForward(swapToLastIndex(state));
-    } else {
-        return moveForward(state);
-    }
-}
-
-function swapToLastIndex(state: StepState) : StepState {
-    const { list, index, lastIndex, lastSwapIndex} = state;
-    const newList = list.slice(0, lastSwapIndex)
-                        .concat(list[index])
-                        .concat(list.slice(lastSwapIndex, index))
-                        .concat(list.slice(index + 1, lastIndex));
-    return { ...state,
-        list: newList,
-        numOfSwaps: state.numOfSwaps + 1, 
-        lastSwapIndex: state.lastSwapIndex + 1,
-    }
-}
-
-function moveForward(state: StepState) : StepState {
-    return { ...state, index: state.index+1 }
-}
-
-function nextCount(state: StepState) : StepState {
-    return { ...state, counter: state.counter + 1, index: state.lastSwapIndex}
-}
-
-
-function useCountingSort(list: number[], time: number) {
-    const [items, setItems] = React.useState(list);
-    const [highlight, setHighlight] = React.useState(0);
-    const [stepState, setStepState] = React.useState<StepState>({
-        list: items,
-        index: 0,
-        lastIndex: items.length,
-        counter: 0,
-        numOfSwaps: 0,
-        lastSwapIndex: 0,
-    });
-
-    React.useEffect(() => {
-        const timeout = setTimeout(() => {
-            setStepState(
-                countingSortStep(stepState)
-            );
-            setItems(stepState.list);
-            setHighlight(stepState.index);
-        }, time);
-        return () => { clearTimeout(timeout) }
-    }, [stepState, time])
-
-    return {
-        items,
-        highlight
-    }
-}
-
-export { useCountingSort };
\ No newline at end of file