Java实现-删除数字

public class Solution {
    /**
     *@param A: A positive integer which has N digits, A is a string.
     *@param k: Remove k digits.
     *@return: A string
     */
    public String DeleteDigits(String A, int k) {
        // write your code here
        if(k==0){
			int countZero=0;
			for(int i=0;i<A.length();i++){
				if(A.charAt(i)!='0')
					break;
				else{
					countZero++;
				}
			}
			return A.substring(countZero);
		}
		int []dp=countLow(A);
		int index=A.length()-1;
		for(int i=0;i<A.length()-1;i++){
			if(dp[i]>dp[i+1]){
				index=i;
				break;
			}
		}
		String front=A.substring(0, index);
		String tail=A.substring(index+1);
		return DeleteDigits(front+tail, k-1);

    }
    private static int[] countLow(String A){
		int []dp=new int[A.length()];
		int []standard=new int[10];
		for(int i=A.length()-1;i>=0;i--){
			 int temp=Integer.parseInt(A.charAt(i)+"");
			 standard[temp]++;
			 for(int j=0;j<temp;j++){
				 dp[i]+=standard[j];
			 }
		}
		return dp;
	}

}