java: use StringBuilder to insert at the beginning

java string insert append stringbuilder

StringBuilder sb = new StringBuilder();for(int i=0;i<100;i++){    sb.insert(0, Integer.toString(i));}

Warning: It defeats the purpose of StringBuilder, but it does what you asked.

Better technique (although still not ideal):

This will turn an O(n²) solution into O(n).

java string insert append stringbuilder

you can use strbuilder.insert(0,i);

java string insert append stringbuilder

Maybe I'm missing something but you want to wind up with a String that looks like this, "999897969594...543210", correct?

StringBuilder sb = new StringBuilder();for(int i=99;i>=0;i--){    sb.append(String.valueOf(i));}

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