面试-算法01

/**
* 打印九九乘法口诀 方法一
*/
public void chengfa(){
for(int i=1;i<=9;i++){
int j = 1;
while(j<=i){
System.out.print(j+"*"+i+"="+i*j+ " ");
j++;
}
System.out.println();

}
}

/**
* 打印九九乘法口诀 方法二
*/
public void chengfa2(){
for(int i =1,j =1;j <=9;i++){
System.out.print(i+"*"+j+"="+i*j+" ");
if(i==j){
i=0;
j++;
System.out.println();
}
}
}

/**
*去除字符串中多余的空格，只保留一个
*/
public void removeEmptySpace(){
String testStr = "I am   happy to   introduce  myself to  you here!";
StringBuffer sb = new StringBuffer();
boolean flg = false;
for(int i=0;i<testStr.length();i++){
char cha = testStr.charAt(i);
//System.out.println(cha);
if(cha == ' '&& flg){
sb.append(cha);
flg = false;
}else if(cha != ' '){
flg =true;
sb.append(cha);
}
}
System.out.println(sb.toString());
}

/**
* 压缩字符串
* Compress :AAABCCf  ==> 3AB2Cf
*/
public void compressText(String text){
int sum =0;
StringBuffer sb = new StringBuffer();
char tmp ;
for(int i=0;i<text.length();i++){
char cha = text.charAt(i);
tmp = (i>0)?text.charAt(i-1):text.charAt(i);
if(tmp == cha){
sum ++;
if(i ==text.length()-1){
sb.append(sum>1?(sum+""+tmp):tmp);
}
}else{
sb.append(sum>1?(sum+""+tmp):tmp);
sum = 1;
tmp = text.charAt(i);

if(i ==text.length()-1){
sb.append(tmp);
}
}
}
System.out.println("compressText is:"+sb.toString());
}