使用vue和elementui写一段前端代码，第一行是一个下拉框，第二行是2个input，最后一行是一个可以使用树形数据的table表格并且有分页功能，表格需要自动占满剩余空间，同时页面使用flex布局

以下是可以实现您的要求的前端代码示例：

<template>
  <div class="container">
    <div class="dropdown">
      <el-select v-model="selectedOption" placeholder="请选择">
        <el-option v-for="item in options" :key="item.value" :label="item.label" :value="item.value"></el-option>
      </el-select>
    </div>
    <div class="input-group">
      <el-input v-model="input1" placeholder="请输入"></el-input>
      <el-input v-model="input2" placeholder="请输入"></el-input>
    </div>
    <div class="table">
      <el-table :data="tableData" style="width: 100%" :row-class-name="tableRowClassName">
        <el-table-column prop="name" label="姓名"></el-table-column>
        <el-table-column prop="age" label="年龄"></el-table-column>
        <el-table-column prop="address" label="地址"></el-table-column>
      </el-table>
      <el-pagination
        class="pagination"
        background
        layout="prev, pager, next"
        :page-size="pageSize"
        :total="totalCount"
        :current-page="currentPage"
        @current-change="handlePageChange"
      ></el-pagination>
    </div>
  </div>
</template>

<script>
export default {
  name: "MyComponent",
  data() {
    return {
      options: [
        { label: "选项1", value: "option1" },
        { label: "选项2", value: "option2" },
        { label: "选项3", value: "option3" },
      ],
      selectedOption: "",
      input1: "",
      input2: "",
      tableData: [
        { name: "张三", age: 18, address: "北京市海淀区" },
        { name: "李四", age: 24, address: "上海市浦东区" },
        { name: "王五", age: 31, address: "广州市天河区" },
        { name: "赵六", age: 42, address: "深圳市南山区" },
      ],
      currentPage: 1,
      pageSize: 2,
      totalCount: 4,
    };
  },
  methods: {
    tableRowClassName({ index }) {
      return index % 2 === 0 ? "even-row" : "odd-row";
    },
    handlePageChange(page) {
      this.currentPage = page;
      // TODO: 根据分页信息查询数据
    },
  },
};
</script>

<style>
.container {
  display: flex;
  flex-direction: column;
  height: 100%;
}

.dropdown {
  margin-bottom: 16px;
}

.input-group {
  display: flex;
}

.input-group > * {
  flex: 1;
  margin-right: 16px;
}

.table {
  flex: 1;
  overflow-y: auto;
  margin-top: 16px;
}

.pagination {
  margin-top: 16px;
  display: flex;
  justify-content: center;
}
</style>

请注意，上面的代码只是一个示例，您可以根据需要进行修改和扩展。如果您不熟悉 Vue 和 Element UI，建议先学习它们的基本用法。