char*s1, const char *s2，删除s1中s2出现过的字符

class Solution {
public:
    char* delChar(char* s1,char* s2)
    {
        if(s1==nullptr)
            return nullptr;
        if(s2==nullptr)
            retrun s1;
        
        const int tableSize=256;
        int table[tableSize];
        for(int i=0;i