RLE全称run-length encoding,又称为游程编码,或者长度编码,变动长度编码法(run coding)。例如,我们输入字符串"qwweeerrrrttttt",经过压缩之后的输出结果应该为"1q2w3e4r5t"。
以下分别使用Java递归和尾递归的方式来实现。
- 递归方式实现
public static String RLECompress(String source) {
if (source.length() <= 1) return source;
int runLength = 1;
while (runLength < source.length() && source.charAt(0) == source.charAt(runLength)) {
runLength++;
}
return runLength + source.substring(0, 1) + RLECompress(source.substring(runLength));
}
- 尾递归方式实现
public static String RLECompressWithTail(String source, String result) {
if (source.length() <= 0) return result;
int runLength = 1;
while (runLength < source.length() && source.charAt(0) == source.charAt(runLength)) {
runLength++;
}
result += runLength + source.substring(0, 1);
return RLECompressWithTail(source.substring(runLength), result);
}
参考
//http://www.6tie.net/p/908340.html