# LeetCode – Remove K Digits (Java)

Given a non-negative integer num represented as a string, remove k digits from the number so that the new number is the smallest possible.

Note:
The length of num is less than 10002 and will be ≥ k.
The given num does not contain any leading zero.

Example 1:

```Input: num = "1432219", k = 3
Output: "1219"
Explanation: Remove the three digits 4, 3, and 2 to form the new number 1219 which is the smallest.
```

Example 2:

```Input: num = "10200", k = 1
Output: "200"
Explanation: Remove the leading 1 and the number is 200. Note that the output must not contain leading zeroes.
```

Example 3:

```Input: num = "10", k = 2
Output: "0"
Explanation: Remove all the digits from the number and it is left with nothing which is 0.
```

Java Solution

```public String removeKdigits(String num, int k) { if(num.length()==k) return "0";   StringBuilder sb = new StringBuilder(num); for(int j=0; j<k; j++){ int i=0; while(i<sb.length()-1&&sb.charAt(i)<=sb.charAt(i+1)){ i++; } sb.delete(i, i+1); }   //remove leading 0's while (sb.length() > 1 && sb.charAt(0)=='0') sb.delete(0,1);   if(sb.length()==0){ return "0"; }   return sb.toString(); }```
Category >> Algorithms
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