Minimum Index Sum of Two Lists

# 599. Minimum Index Sum of Two Lists

Given two arrays of strings list1 and list2, find the common strings with the least index sum.

A common string is a string that appeared in both list1 and list2.

A common string with the least index sum is a common string such that if it appeared at list1[i] and list2[j] then i + j should be the minimum value among all the other common strings.

Return all the common strings with the least index sum. Return the answer in any order.

### Example 1:
```
Input: list1 = ["Shogun","Tapioca Express","Burger King","KFC"], list2 = ["Piatti","The Grill at Torrey Pines","Hungry Hunter Steakhouse","Shogun"]
Output: ["Shogun"]
Explanation: The only common string is "Shogun".
```

### Example 2:
```
Input: list1 = ["Shogun","Tapioca Express","Burger King","KFC"], list2 = ["KFC","Shogun","Burger King"]
Output: ["Shogun"]
Explanation: The common string with the least index sum is "Shogun" with index sum = (0 + 1) = 1.
 ```

Constraints:
```
1 <= list1.length, list2.length <= 1000
1 <= list1[i].length, list2[i].length <= 30
list1[i] and list2[i] consist of spaces ' ' and English letters.
All the strings of list1 are unique.
All the strings of list2 are unique.
```

/**
 * @param {string[]} list1
 * @param {string[]} list2
 * @return {string[]}
 */
 var findRestaurant = function(list1, list2) {
    const map = new Map();
    const getFreqMap = (arr) => {
        for(let i = 0; i < arr.length; i++) {
            if (map.has(arr[i])) {
                const val = map.get(arr[i]).split(':');
                map.set(arr[i], `${+val[0] + 1}:${+val[1] + i}`);
            } else {
                map.set(arr[i], `1:${i}`);
            }
        }
    }  

    getFreqMap(list1); 
    getFreqMap(list2); 

    const freq = 2;
    let min = Infinity, out = [];
    for(const [key, value] of map.entries()) {
        const valParts = value.split(':');
        if (+valParts[0] === freq) {
            if (+valParts[1] < min) {
                out = [key];
                min = +valParts[1];
            } else if (+valParts[1] === min) {
                out.push(key);
            }
        }
    }
    return out;
};