class Solution {
public:
int strToInt(string str) {
int len =str.size();
if(len==0) return 0;
int k=0;
int f=1;
long long ans=0;
while(k<len && str[k]==' ') k++;
if(k<len && str[k]=='-')
{
f=-1;
k++;
}
if(k<len && str[k]=='+') k++;
while(k<len && str[k]<='9' && str[k]>='0')
{
ans= 10*ans + f*(str[k]-'0');
if(ans>INT_MAX) return INT_MAX;
if(ans<INT_MIN) return INT_MIN;
k++;
}
return ans;
}
};