Implement strStr().
Return the index of the first occurrence of needle in haystack, or -1 if needle is not part of haystack.
Clarification:
What should we return when needle is an empty string? This is a great question to ask during an interview.
For the purpose of this problem, we will return 0 when needle is an empty string. This is consistent to C's strstr() and Java's indexOf().
Example 1:
Input: haystack = "hello", needle = "ll" Output: 2
Example 2:
Input: haystack = "aaaaa", needle = "bba" Output: -1
Example 3:
Input: haystack = "", needle = "" Output: 0
Constraints:
0 <= haystack.length, needle.length <= 5 * 104haystack and needle consist of only lower-case English characters.struct Solution;
impl Solution {
fn str_str(haystack: String, needle: String) -> i32 {
match haystack.find(&needle) {
Some(index) => index as i32,
None => -1,
}
}
}
#[test]
fn test() {
assert_eq!(Solution::str_str("hello".to_string(), "ll".to_string()), 2);
assert_eq!(
Solution::str_str("aaaaa".to_string(), "bba".to_string()),
-1
);
}