Java:
class Solution {
public int strStr(String haystack, String needle) {
if (needle.length() == 0) {
return 0;
} else if (haystack.length() == 0) {
return -1;
}
for (int i = 0; i < haystack.length() - needle.length() + 1; i++) {
for (int j = 0; j < needle.length(); j++) {
if (haystack.charAt(i + j) != needle.charAt(j)) {
break;
} else {
if (j == needle.length() - 1) {
return i;
}
}
}
}
return -1;
}
}
class Solution {
public int strStr(String haystack, String needle) {
if (needle.length() == 0) {
return 0;
} else if (haystack.length() == 0) {
return -1;
}
for (int i = 0; i < haystack.length() - needle.length() + 1; i++) {
int flag = i;
for (int j = 0; j < needle.length(); j++) {
if (haystack.charAt(i) == needle.charAt(j)) {
if (j == needle.length() - 1) {
return i - j;
} else {
i++;
}
} else {
i = flag;
break;
}
}
}
return -1;
}
}
Python:
class Solution:
def strStr(self, haystack, needle):
if not needle:
return 0
if not haystack:
return -1
for i in range(0, len(haystack) - len(needle) + 1):
for j in range(0, len(needle)):
if haystack[i + j] != needle[j]:
break
if j == len(needle) - 1:
return i
return -1