Leetcode题解（二）

 1 class Solution {
 2 public:
 3     int myAtoi(string str) {
 4         int index=0;
 5         int flag = 1;
 6         long long res=0;
 7         if(str.length()==0)return 0;
 8         while (str[index]==‘ ‘)//去除空白
 9             index++;
10 
11         if(str[index] == ‘-‘)//负数
12         {
13             flag = -1;
14             index++;
15         }
16         else if(str[index] == ‘+‘)//负数
17         {
18             flag = 1;
19             index++;
20         }
21         int len = str.length();
22         while (str[index]>=‘0‘&&str[index]<=‘9‘)
23         {
24             res = res * 10 +str[index]-‘0‘;
25             if(res > INT_MAX)
26                 return flag>0 ? INT_MAX:INT_MIN;
27             index++;
28         }
29 
30         return res*flag;
31     }
32 };

 1 class Solution {
 2 public:
 3     bool isPalindrome(int x) {
 4         if (x == -2147483648)
 5         {
 6             return false;
 7         }
 8         if (x<0)
 9         {
10             //x=0-x;
11             return false;
12         }
13         int length = (int)log10(x*1.0)+1;//判断x的位数
14         //int s[20];
15         int temp1 = x;
16         int temp2 = x;
17         int middle = length/2;
18         int i,j,left,right,power=length-1;
19         for (i=1;i<=middle;i++)
20         {
21             left=temp1/(int)pow(10.0,power);
22             temp1=temp1%(int)pow(10.0,power);
23             power--;
24 
25             right = temp2%10;
26             temp2 = temp2/10;
27             if (left != right)
28             {
29                 return false;
30             }
31 
32         }
33         return true;
34     }
35 };