Time: 3 ms (59.08%), Space: 6.6 MB (26.15%) - LeetHub

Author: MishkatIT

0008-string-to-integer-atoi/0008-string-to-integer-atoi.cpp

@@ -0,0 +1,76 @@
+class Solution {
+public:
+    int myAtoi(string s) {
+        string ans;
+        bool neg = false, pos = false;
+        bool word = false;        
+        for (int i = 0; i < s.length(); i++)
+        {
+            if(s[i] == '-')
+                {
+                    if(ans.size())
+                        break;
+                    if(pos || ans.size() || neg)
+                        return 0;
+                    else    
+                        neg = true;
+                }
+            else if(s[i] == '+')
+                {
+                    if(ans.size())
+                        break;
+                    if(neg || ans.size() || pos)
+                        return 0;
+                    else
+                        pos = true;    
+                }  
+            else if(s[i] == ' ')
+                {
+                    if(ans.size())
+                        break;
+                    if(pos || neg)
+                        return 0;    
+                }    
+            else if(s[i] == '.')
+                ans.push_back('.');    
+            else if((s[i] >= 'a' && s[i] <= 'z') ||(s[i] >= 'A' && s[i] <= 'Z')) 
+            {
+                word = true;
+                if(!ans.size())
+                    return 0;
+                if(ans.size())
+                    break;    
+            }
+            else if(s[i] >= '0' && s[i] <= '9')
+            {
+                if(word)
+                    return 0;
+                ans.push_back(s[i]);
+            }    
+        }
+        int k;
+        for (k = 0; k < ans.length(); k++)
+        {
+            if(ans[k] != '0')
+                break;
+        }
+        ans = ans.substr(k);
+        long long num = 0;
+        for (int i = 0; i < ans.length(); i++)
+        {
+            if(ans[i] == '.')
+                break;
+            num = num * 10 + (ans[i] - '0');
+            if(num > INT_MAX)
+            {
+                if(neg)
+                    return INT_MIN;
+                else
+                    return INT_MAX;    
+            }
+        }
+        if(neg)
+            num *= -1;
+        return num;    
+    }
+};