"Leetcode-Interview algorithm classic-java Implementation" "028-implement StrStr () (Implement STRSTR () function)"

"028-implement strStr () (Implement STRSTR () function)" "leetcode-Interview algorithm classic-java Implementation" "All topics Directory Index" Original Question

Implement strStr ().
Returns the index of the first occurrence of needle in haystack, or-1 if needle are not part of haystack.

Main Topic

Implement the STRSTR () function to determine where a string appears in another string. If it does not match, return-1.

Thinking of solving problems

Implementation using the KMP algorithm

Code Implementation

Algorithm implementation class

public class Solution {publicintSTRSTR (String haystack, string needle) {if(haystack = = NULL | | needle = = NULL) {return-1; }if(Needle.length() > Haystack.length()) {return-1; }if("". Equals (haystack)) {if("". Equals (needle)) {return 0; }Else{return-1; }        }Else{if("". Equals (needle)) {return 0; }        }returnKmpindex (haystack, needle); } privateintKmpindex (String haystack, string needle) {inti =0;intj =0;int[]Next=Next(needle); while(I < haystack.length() && J < Needle.length()) {if(j = =-1||                Haystack.charat (i) = = Needle.charat (j)) {++i;            ++j; }Else{j =Next[j]; }        }if(j = = needle.length()) {returnI-j; }Else{return-1; }} Privateint[]Next(String needle) {int[]Next= newint[Needle.length()];Next[0] = -1;inti =0;intj =-1;intK = needle.length() -1; while(I < k) {if(j = =-1||                Needle.charat (i) = = Needle.charat (j)) {++i; ++j;if(Needle.charat (i)! = Needle.charat (j)) {Next[I] = j; }Else{Next[I] =Next[j]; }            }Else{j =Next[j]; }        }return Next; }}

Evaluation Results

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"Leetcode-Interview algorithm classic-java Implementation" "028-implement StrStr () (Implement STRSTR () function)"