Cardinal sorting is an independent sorting idea, and its sorting criterion is "group by bit, then sort by row", which is suitable for sorting with different digits. The code is as follows:
public static void radixSort(int[]arr){
int [][] temp = new int[10][arr.length];
int max = Integer.MIN_VALUE; //存最大数
int [] counts = new int[10];
for(int i=0;i<arr.length;i++){
if(arr[i] > max){
max = arr[i];
}
}
int maxLength = (max+"").length; //求最大数位数
for(int i=0,n=1;i<maxLength;i++,n*=10){
//决定循环次数
for(int j=0;j<arr.length;j++){
int ys = arr[j]/n%10;
temp[ys][counts[ys]] = arr[j];
counts[ys]++;
}
if(i==0){
for(int[]nums:temp){
System.out.println(Arrays.toString(nums));
}
}
for(int k=0;k<counts.length;k++){
if(counts[k]!=0){
for(int l=0;l<counts[k];l++){
arr[index]++ = temp[k][l];
}
counts[k] = 0;
}
}
}
}