Meta E4 Phone Screen Round

Round 1

Questions:

1. 791 Custom Sort String Link

   public String customSortString(String order, String s) {
       Map<Character, Integer> map = new HashMap<>();
       int n = s.length();
       int m = order.length();
       
       for(int i=0; i<n; i++) {
           char letter = s.charAt(i);
           map.put(letter, map.getOrDefault(letter,0)+1);
       }
   
       StringBuilder result = new StringBuilder();
   
       for(int i =0; i<m; i++) {
           char letter = order.charAt(i);
           if(map.containsKey(letter)) {
               int count = map.get(letter);
               while(count-- > 0) {
                   result.append(letter);
                   map.put(letter,count);
               }
           }
       }
   
       for(char key : map.keySet()) {
           int count = map.get(key);
           while(count > 0) {
               result.append(key);
               count--;
           }
       }
       return result.toString();
   }

2. Plan a round trip between 2 cities with minimum flight cost. Given 2 arrays - Departure costs and Return Costs. Both arrays will always have the same size. D = [10, 8, 9, 11, 7]
   R = [8, 8, 10, 7, 9]
   Ans = 15 (8+7); Note: It cannot be 7+7 as you can't take return flight without taking departure flight.

   public static int minFlightCost(int[] D, int[] R) {
       int n = D.length;
       int minDep = Integer.MAX_VALUE;
       int minRT = Integer.MAX_VALUE;
   
       for (int i = 0; i < n; i++) {
           if (i > 0) {
               minRT = Math.min(minRT, minDep + R[i]);
           }
           minDep = Math.min(minDep, D[i]);
       }
       return minRT;
   }