Replacement of spaces in strings (Java version)

Replacement of spaces in strings (Java version)

Solution 1: Time complexity is O (n ^ 2)

Solution 2: The time complexity is O (n)

Code implementation: <喎?http: www.bkjia.com kf ware vc " target="_blank" class="keylink"> Vc3ryb25np1_vcd4ncjxwcmugy2xhc3m9 "brush: java;"> Package string; public class SpaceStringReplace2 {// len is the total capacity of the array size public static void SpaceReplace (String strOld, int len) {char [] chs = new char [len]; char [] ch = strOld. toCharArray (); for (int I = 0; I <ch. length; I ++) {chs [I] = ch [I];} int strOldLen = 0; int blackString = 0; if (chs = null | len <= 0) {new NullPointerException ();} int I = 0; while (chs [I]! = '\ 0') {strOldLen ++; if (chs [I] = '') {blackString ++;} I ++ ;} // convert the space to % 20 characters in length int strNewLen = strOldLen + blackString * 2; if (strNewLen> len) {new ArrayIndexOutOfBoundsException ();} int indexOfOld = strOldLen; // point to '\ 0' int indexOfNew = strNewLen; while (indexOfOld> 0 & indexOfNew> indexOfOld) {if (chs [indexOfOld] = '') {chs [indexOfNew --] = '0'; chs [indexOfNew --] = '2'; chs [indexOfNew --] = '% ';} else {chs [indexOfNew --] = chs [indexOfOld];} -- indexOfOld;} for (char c: chs) {if (c = '\ 0') {break ;} system. out. print (c);} System. out. println ();} public static void main (String [] args) {// StringBuilder str = new StringBuilder ("We are happy. "); long timelast = System. currentTimeMillis (); String str = "We are happy. "; SpaceReplace (str, 100); // We % 20are % 20happy. long timeafter = System. currentTimeMillis (); System. out. println (timeafter-timelast );}} Solution 3: JDK built-in string Cutting

Code implementation:

package string;public class SpaceStringReplace { public static String SpaceReplace(String strOld){ String[] split = strOld.split(" "); StringBuilder stringBuilder = new StringBuilder(); for (int i = 0; i < split.length-1; i++) { stringBuilder.append(split[i]).append("%20"); } stringBuilder.append(split[split.length-1]); String strNew = stringBuilder.toString(); return strNew; } public static void main(String[] args) { //StringBuilder str = new StringBuilder("We are happy."); String str = "We are happy."; System.out.println(SpaceReplace(str));//We%20are%20happy. }}