leetCode/1207.独一无二的出现次数.html

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    <title>1207. 独一无二的出现次数</title>
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    <script>
      // https://leetcode.cn/problems/unique-number-of-occurrences/

      // 给你一个整数数组 arr，请你帮忙统计数组中每个数的出现次数。
      // 如果每个数的出现次数都是独一无二的，就返回 true；否则返回 false。
      // 提示：
      // 1 <= arr.length <= 1000
      // -1000 <= arr[i] <= 1000

      /**
       * @param {number[]} arr
       * @return {boolean}
       */
      var uniqueOccurrences = function (arr) {};

      // --- answer-1 ---

      // 计数
      var uniqueOccurrences = function (arr = []) {
        const count = arr.reduce((pre, cur) => {
          pre[cur] = (pre[cur] || 0) + 1;
          return pre;
        }, {});
        const hash = {};
        for (let k in count) {
          const val = count[k];
          if (val in hash) return false;
          hash[val] = 1;
        }
        return true;
      };

      // --- answer-1 ---

      // --- answer-2 ---

      // --- answer-2 ---

      var arr = [1, 2, 2, 1, 1, 3];
      var result = true;
      // 解释：在该数组中，1 出现了 3 次，2 出现了 2 次，3 只出现了 1 次。没有两个数的出现次数相同。

      var arr = [1, 2];
      var result = false;

      var arr = [-3, 0, 1, -3, 1, 1, 1, -3, 10, 0];
      var result = true;

      console.log('arr = ', arr);
      console.log('result = ', result);
      console.log('uniqueOccurrences = ', uniqueOccurrences(arr));
    </script>
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