看的見得算法 第四章 排序算法可視化

4-1

SelectionSortData.java

public class SelectionSortData {
    private int[] numbers;//數據
    public SelectionSortData(int N, int randomBound){
        numbers = new int[N];
        for( int i = 0 ; i < N ; i ++)
            numbers[i] = (int)(Math.random()*randomBound) + 1;
    }
    public int N(){
        return numbers.length;
    }
    public int get(int index){
        if( index < 0 || index >= numbers.length)
            throw new IllegalArgumentException("Invalid index to access Sort Data.");
        return numbers[index];
    }
    public void swap(int i, int j) {
        if( i < 0 || i >= numbers.length || j < 0 || j >= numbers.length)
            throw new IllegalArgumentException("Invalid index to access Sort Data.");
        int t = numbers[i];
        numbers[i] = numbers[j];
        numbers[j] = t;
    }
}

AlgoFrame.java

    private SelectionSortData data;
    public void render(SelectionSortData data){
        this.data = data;
        repaint();
    }

 // TODO： 繪製自己的數據data
            int w = canvasWidth/data.N();
            for(int i = 0 ; i < data.N() ; i ++ ) {
                AlgoVisHelper.setColor(g2d, AlgoVisHelper.LightBlue);
                AlgoVisHelper.fillRectangle(g2d, i * w, canvasHeight - data.get(i), w - 1, data.get(i));
            }

AlgoVisualizer.java

 // 動畫邏輯
    private void run(){
        // TODO: 編寫自己的動畫邏輯
        frame.render(data);
        AlgoVisHelper.pause(DELAY);
        for( int i = 0 ; i < data.N() ; i ++ ){
            // 尋找[i, n)區間裏的最小值的索引
            int minIndex = i;
            for( int j = i + 1 ; j < data.N() ; j ++ ){
                frame.render(data);
                AlgoVisHelper.pause(DELAY);
                if( data.get(j) < data.get(minIndex) ){
                    minIndex = j;
                    frame.render(data);
                    AlgoVisHelper.pause(DELAY);
                }
            }
            data.swap(i , minIndex);
            frame.render(data);
            AlgoVisHelper.pause(DELAY);
        }
        frame.render(data);
        AlgoVisHelper.pause(DELAY);
    }