【LeetCode刷題記錄】8. 字符串轉換整數 (atoi)

題目描述：


題解：
思路比較簡單，這樣寫代碼比較簡潔：

int myAtoi(string str) {
 int len = int(str.size());
 int rst = 0;
 int sign = 1;
 bool started = false;
 for (int i = 0; i < len; i++) {
  if (str[i] == ' ' && rst == 0 && !started)continue;
  if ((str[i] == '-' || str[i] == '+') && rst == 0 && !started) {
   sign = str[i] == '-' ? -1 : 1;
   started = true;
   continue;
  }
  if (int(str[i]) < 48 || int(str[i]) > 57)break;
  started = true;
  int pop = sign*(int(str[i]) - 48);
  if (rst < INT32_MIN / 10 || (rst == INT32_MIN / 10 && pop < -8))return (INT32_MIN);
  if (rst > INT32_MAX / 10 || (rst == INT32_MAX / 10 && pop > 7))return(INT32_MAX);
  rst = 10 * rst + pop;
 }
 return rst;
}

取得了較好的運行結果，提交三次：