class Solution {
public:
    int strToInt(string str) {
        long long res = 0;
        bool is_minus = false;

        int k = 0;
        int n = str.size();
        while(k < n && str[k] == ' ') k++;
        //cout << str[k] << endl;

        if(str[k] == '-') is_minus = true,k++;
        if(str[k] == '+') k++;

        for(int i = k;i < n && str[i] >= '0' && str[i] <= '9';++i){
            res = res * 10 + str[i] - '0';
        }

        if(is_minus) res *= -1;

        if(res < INT_MIN) res = INT_MIN;
        if(res > INT_MAX) res = INT_MAX;
        return res;
    }
};