//方式一
public class StringDemo {
public String reverse(String str,int startIndex,int endIndex){
if(str != null){
char[] arr = str.toCharArray();
for (int x = startIndex, y = endIndex; x < y; x++, y--) {
char temp = arr[x];
arr[x] = arr[y];
arr[y] = temp;
}
return new String(arr);
}
return null;
}
获取一个字符串在另一个字符串中出现的次数
比如 获取 “ab”在 “absddabddabab”出现的次数
public class StringDemo1 {
public int getCount(String mainStr,String subStr) {
int mainLength = mainStr.length();
int subLength = subStr.length();
int count = 0;
int index = 0;
if (mainLength > subLength) {
if (mainLength > subLength) {
//方式一
// while((index = mainStr.indexOf(subStr)) != -1) {
// count++;
// mainStr = mainStr.substring(index + subStr.length());
// }
//改进
while((index = mainStr.indexOf(subStr,index)) != -1){
count++;
index += subLength;
}
return count;
}else {
return 0;
}
}
}
获取两个字符串的最大相同子串:
比如:str1 = “abcwerthelloyuiodef ” str2 = "cvhellobnm"
提示:将短的哪个进行长度依次递减的子串与较长的串比较
public class StringDemo2 {
public String getMaxSameString(String str1, String str2) {
if (str1 != null && str2 != null) {
String maxStr = (str1.length() >= str2.length()) ? str1 : str2;
String minStr = (str1.length() < str2.length()) ? str1 : str2;
int length = minStr.length();
for (int i = 0; i < length; i++) {
for (int x = 0, y = length - i; y <= length; x++, y++) {
String subStr = minStr.substring(x, y);
if (maxStr.contains(subStr)) {
return subStr;
}
}
}
}
return null;
}