leetcode 8 字符串转换整数 (atoi)

最新推荐文章于 2024-09-29 19:46:50 发布

weixin_40161962

最新推荐文章于 2024-09-29 19:46:50 发布

阅读量83

点赞数

本文链接：https://blog.youkuaiyun.com/weixin_40161962/article/details/101164894

版权

class Solution {
   public int myAtoi(String str) {
   char[] c1 = str.toCharArray();
   int i = 0;
   int sum = 0;
   boolean flag = true;
if (c1.length == 0)return 0;
   while(c1[i] == ' ') {
       if (i == c1.length-1) {
              return 0;
          }
       i++;

   }
   for(;i < c1.length;i++) {
       if(c1[i] == '-') {
           if (i > 0 && isnum(c1[i-1])) return flag?sum:-sum;
               if (i < c1.length-1 && isnum(c1[i+1])) {
                   flag = false;
               }else {
                   return 0;
               }
continue;
       }
if(c1[i] == '+') {
      if (i > 0 && isnum(c1[i-1])) return flag?sum:-sum;
               if (i == c1.length-1 || !isnum(c1[i+1])) {
                   return 0;
               }
               continue;
       }
       if (isnum(c1[i])) {
           if(flag && (sum > Integer.MAX_VALUE/10 || (sum == Integer.MAX_VALUE/10 && c1[i] > '7'))) {
               return Integer.MAX_VALUE;
           }
           if (!flag && (sum > Integer.MAX_VALUE/10 || (sum == Integer.MAX_VALUE/10 && c1[i] > '8'))) {
                   return Integer.MIN_VALUE;
               }
               sum = sum*10 + c1[i]-'0';
           }
       else {
           return flag?sum:-sum;
       }
   }
   return flag?sum:-sum;
   }
   boolean isnum(char c) {
       if(c >= '0' && c <= '9') {
           return true;
       }else {
           return false;
       }
   }
   }