Fair Pay - Amazon Top Interview Questions


Problem Statement :


You are given a list of integers ratings representing the performance scores of programmers. The manager would like to give $1 to every programmer except if two programmers are adjacent, they'd like to pay the better performing programmer at least $1 higher than the worse performing one.

Return the minimum amount of dollars the manager can pay following above constraints.

Constraints

n ≤ 100,000 where n is the length of ratings.

Example 1

Input

ratings = [1, 2, 5, 1]

Output

7

Explanation

The minimum we can pay for each respective programmer is [1, 2, 3, 1]


Solution :



title-img 




                        Solution in C++ :

vector<int> left(r.size(), 1), right(r.size(), 1);
for  (int i=1; i<r.size(); i++) {
    if (r[i] > r[i-1]) left[i] = left[i-1] + 1;
}
for (int i=r.size()-2; i>=0; i--) {
    if (r[i] > r[i+1]) right[i] = right[i+1] + 1;
}

int ans = 0;
for (int i=0; i<r.size(); i++) ans += max(left[i], right[i]);
return ans;
                    


                        Solution in Java :

import java.util.*;

class Solution {
    public int solve(int[] ratings) {
        if (ratings.length == 0)
            return 0;
        int[] left = new int[ratings.length];
        int[] right = new int[ratings.length];
        left[0] = 1;
        for (int i = 1; i < ratings.length; i++) {
            if (ratings[i] > ratings[i - 1]) {
                left[i] = (1 + left[i - 1]);
            } else
                left[i] = 1;
        }
        right[ratings.length - 1] = 1;
        for (int i = ratings.length - 2; i >= 0; i--) {
            if (ratings[i] > ratings[i + 1]) {
                right[i] = 1 + right[i + 1];
            } else
                right[i] = 1;
        }
        // System.out.println(Arrays.toString(left));
        // System.out.println(Arrays.toString(right));
        int[] pay = new int[ratings.length];
        int cnt = 0;
        for (int i = 0; i < ratings.length; i++) {
            pay[i] = Math.max(left[i], right[i]);
            cnt += pay[i];
        }
        return cnt;
    }
}
                    


                        Solution in Python : 
                            
class Solution:
    def solve(self, ratings):
        if not ratings:
            return 0
        n = len(ratings)
        up = down = peak = 0
        res = 1
        for i in range(1, n):
            if ratings[i - 1] < ratings[i]:
                # going up case
                up += 1
                peak = up
                down = 0
                # 1 basic pay + up amount based on previous chain of increasing ratings
                res += 1 + up
            elif ratings[i - 1] == ratings[i]:
                up = down = peak = 0
                res += 1
            else:
                up = 0
                down += 1
                # down amount for chain of decreasing ratings + 1 basic pay if previous peak is smaller than current
                res += down
                if peak < down:
                    res += 1
        return res


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