java: use StringBuilder to insert at the beginning
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): Reverse each string you want to insert. Append each string to a StringBuilder. Reverse the entire StringBuilder when you’re done. This will turn an O(n²) solution … Read more
