Merge pull request neetcode-gh#1021 from julienChemillier/patch-3

Add 5 in language c

c/5-Longest-Palindromic-Substring.c

@@ -0,0 +1,42 @@
+
+/*
+Given a string s, return the longest palindromic substring in s.
+Time: O(n^2)
+Space: O(1)
+*/
+
+char* longestPalindrome(char * s){
+ int pos=0;
+ int lenmax=1;
+ for (int i=0; s[i]!='\0'; i++){
+ int g=i, d=i;
+ while (g>=0 && s[d]!='\0' && s[g]==s[d]){ 
+ g-=1;
+ d+=1;
+ }
+ d--;
+ g++;
+ if (d-g>=lenmax){
+ lenmax=d-g+1;
+ pos=g;
+ }
+ g=i,d=i+1;
+ while (g>=0 && s[d]!='\0' && s[g]==s[d]){
+ g-=1;
+ d+=1;
+ }
+ d--;
+ g++;
+
+ if (d-g>=lenmax){
+ lenmax=d-g+1;
+ pos=g;
+ }
+ }
+ char* new_s = (char*)malloc(sizeof(char)*(lenmax+1));
+ new_s[lenmax]='\0';
+ for (int i=0; i<lenmax; i++){
+ new_s[i]=s[i+pos];
+ }
+ return new_s;
+}