Why am I getting "Runtime Error: AddressSanitizer: DEADLY SIGNAL"?

Last time I tried to solve a problem in leetcode but my solution is getting "Runtime Error: AddressSanitizer: DEADLY SIGNAL".

The complete Error message is

AddressSanitizer:DEADLYSIGNAL ================================================================= ==30==ERROR: AddressSanitizer: SEGV on unknown address (pc 0x0000002b0452 bp 0x7ffd8e6682e0 sp 0x7ffd8e667a78 T0) ==30==The signal is caused by a READ memory access. ==30==Hint: this fault was caused by a dereference of a high value address (see register values below). Dissassemble the provided pc to learn which register was used. #3 0x7f73671f7d6b (/lib/x86_64-linux-gnu/libstdc++.so.6+0x144d6b) #10 0x7f7366d6b0b2 (/lib/x86_64-linux-gnu/libc.so.6+0x270b2) AddressSanitizer can not provide additional info. ==30==ABORTING

The problem link is https://leetcode.com/problems/word-pattern/

Here is my solution

class Solution {
public:
bool wordPattern(string pattern, string s) {
    vector<string>vec;
    string tmp = "";
    for(int i=0 ; i<s.size() ; i++){
        if(s[i] == ' '){
            vec.push_back(tmp);
            tmp.clear();
            continue;
        }
        tmp += s[i];
    }
    map<char , set<string> > mp;
    for(int i=0 ; i<pattern.size() ; i++){
        mp[pattern[i]].insert(vec[i]);
    }
    bool flag = 0;
    for(int i=0 ; i<pattern.size() ; i++){
        char x = pattern[i];
        if(mp[x].size() != 1)
            flag = 1;
    }
    return !flag;
}

};

I don't get where is the problem...