Implement strStr() Problem Solution

Implement strStr() Problem: Given two strings `needle` and `haystack`, return the index of the first occurrence of `needle` in `haystack`, or `-1` if `needle` is not part of `haystack`.

Example 1:

Input: haystack = “sadbutsad”, needle = “sad” Output: 0 Explanation: “sad” occurs at index 0 and 6. The first occurrence is at index 0, so we return 0.

Example 2:

Input: haystack = “leetcode”, needle = “leeto” Output: -1 Explanation: “leeto” did not occur in “leetcode”, so we return -1.

Problem Solution In Python

``````class Solution:
def strStr(self, haystack: str, needle: str) -> int:
try:
return 0 if len(needle) == 0 else haystack.index(needle, 0, len(haystack))
except:
return -1
``````

Problem Solution In Java

``````class Solution {
public int strStr(String haystack, String needle) {
return haystack.indexOf(needle);
}
}
``````

Problem Solution In C++

``````class Solution {
public:
int strStr(string haystack, string needle)
{
if(needle==" ")
return 0;
if(haystack.find(needle)!=string::npos)
return haystack.find(needle);
return -1;
}
};
``````

Problem Solution In C

``````int strStr(char * haystack, char * needle)
{
int len = strlen(haystack),j;
int l=strlen(needle);

if(l==0)
return 0;

if(len<l)
return -1;

for(int i=0;i<len;i++)
{
for(j=0;j<l;j++)
{
if(haystack[i+j]!=needle[j])
break;
}
if(j==l)
return i;
}
return -1;
}``````

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