判断字符串是否为回文

{
  "problem": {
    "name": "判断字符串是否为回文",
    "description": {
      "content": "输入一个字符串，输出该字符串是否回文。回文是指顺读和倒读都一样的字符串。",
      "description_type": "Markdown"
    },
    "platform": "Luogu",
    "limit": {
      "time_limit": 1000,
      "memory_limit": 131072
    },
    "difficulty": {
      "LuoguStyle": "P1"
    },
    "is_remote": true,
    "is_sync": true,
    "sync_url": null,
    "sign": "LGB2124"
  },
  "statements": [
    {
      "statement_type": "Markdown",
      "content": "输入一个字符串，输出该字符串是否回文。回文是指顺读和倒读都一样的字符串。\n\n## Input\n\n输入一行字符串，长度小于 $100$。\n\n## Output\n\n如果字符串是回文，输出 `yes`；否则，输出 `no`。\n\n[samples]...",
      "is_translate": false,
      "language": "English"
    }
  ]
}