# Leetcode 1365

<!--toc:start-->
- [Leetcode 1365](#leetcode-1365)
  - [Creating a Frequancy Map](#creating-a-frequancy-map)
    - [Hammer Tool](#hammer-tool)
<!--toc:end-->

```js
function reduceArray(nums) {
  const sorted = [...nums].sort((a, b) => a - b)
  return nums.map((x) => {
   nums.indexOf(sorted[x]) 
  })
}
```

## Creating a Frequancy Map

```js
function reduceArray(nums) {
  const freqMap = new Map()
  nums.forEach((x) => {
    if (freqMap.has(x)) {
      freqMap.set(x, freqMap.get(x) + 1)
    } else {
      freqMap.set(x, 1)
    }
  })
  return Array.from(freqMap.entries()).map(([k, v]) => v)
}
```

### Hammer Tool

```js
function hammer(arrOrStr) {
    const freq = {};
    for (let item of arrOrStr) {
        freq[item] = (freq[item] || 0) + 1;
    }
    
    // Then either:
    // A. Return freq map
    // B. Sort using freq
    return arrOrStr.slice().sort((a, b) => {
        if (freq[b] !== freq[a]) return freq[b] - freq[a]; // desc freq
        return a < b ? -1 : 1; // tiebreaker
    });
}
```