14. Longest Common Prefix

public String longestCommonPrefix(String[] strs) {
if(strs == null || strs.length == 0) {
return "";
}
int min = minLen(strs);
int cnt = 0;
for(int i = 0; i < min; i++) {
char c = strs[0].charAt(i);
cnt++;
for(int j = 1; j < strs.length; j++) {
if(strs[j].charAt(i) != c) {
return strs[0].substring(0, cnt - 1);
}
}
}
return strs[0].substring(0,cnt);
}

private int minLen(String[] strs) {
int minLen = Integer.MAX_VALUE;
for(int i = 0; i < strs.length; i++) {
minLen = Math.min(minLen, strs[i].length());
}
return minLen;
}