[Leetcode] 14. Longest Common Prefix (C)

char* longestCommonPrefix(char** strs, int strsSize) {
    char* common = strs[0];

    int common_last = strlen(common);

    for(int i = 1; i<strsSize; i++)
    {
        char* compare = strs[i];

        int common_current =0;
        int compare_current =0;

        while(common_current<common_last && compare_current <common_last)
        {
            if(common[common_current]==compare[compare_current])
            {
                common_current++;
                compare_current++;
            }else{
                if(common_last>common_current)
                    common_last = common_current;
                break;
            }

        }  
    }
    char* res = (char *)malloc(sizeof(char) * (common_last+1));
    strncpy(res,common,common_last);
    res[common_last]='\0';
    return res;
}

#include <string.h>
char *strstr(const char *string1, const char *string2);

int main() {
    char* a = "hello";
    char* b = "";
    printf("%c",*strstr(a,b)+1); //output : h
}

char* longestCommonPrefix(char** strs, int strsSize) {
    if(strsSize==0){
        return 0;
    }
    char* common = strs[0];
    for(int i =0; i<strsSize; i++){
        while(*common){
            if(strstr(strs[i],common)!=strs[i]){
                common[strlen(common)-1]='\0';
            }else{
                break;
            }
        }
        
    }
    return common;
}

char* longestCommonPrefix(char** strs, int strsSize) {
    char* common = strs[0];

    int common_last = strlen(common);

    for(int i = 1; i<strsSize; i++)
    {
        char* compare = strs[i];

        int common_current =0;
        int compare_current =0;

        while(common_current<common_last && compare_current <common_last)
        {
            if(common[common_current]==compare[compare_current])
            {
                common_current++;
                compare_current++;
            }else{
                if(common_last>common_current)
                    common_last = common_current;
                break;
            }

        }  
    }
    common[common_last] = '\0';
    return common;
}