public class StrStr {

// 相当于java indexOf

public int indexOf(String source,String pattern){

char first = pattern.charAt(0);

int max = source.length()-pattern.length();

for (int index = 0; index <= max; index++) {

if (source.charAt(index) != first) {

while(++index <= max && source.charAt(index) != first);

}

if (index <= max) {

int rest = index + 1;

int end = index + pattern.length();

for (int k = 1; rest < end && source.charAt(rest) == pattern.charAt(k); k++,rest++);

if (rest == end) {

return index;

}

}

}

return -1;

}

public static void main(String[] args) {

StrStr instance = new StrStr();

String source = "sfaba bcasf babca bcab ababcabababbabcab";

String pattern = "abababb";

int index = instance.indexOf(source, pattern);

if(index >= 0){

System.out.println(index);

}

else{

System.out.println("No contain");

}

}

}