You are given two integer arrays nums and multipliers of size n and m respectively, where n >= m. The arrays are 1-indexed.
You begin with a score of 0. You want to perform exactly m operations. On the ith operation (1-indexed), you will:
Choose one integer x from either the start or the end of the array nums.
Add multipliers[i] * x to your score.
Remove x from the array nums.
Return the maximum score after performing m operations.
Example 1:
Input: nums = [1,2,3], multipliers = [3,2,1]
Output: 14
Explanation: An optimal solution is as follows:
- Choose from the end, [1,2,3], adding 3 * 3 = 9 to the score.
- Choose from the end, [1,2], adding 2 * 2 = 4 to the score.
- Choose from the end, [1], adding 1 * 1 = 1 to the score.
The total score is 9 + 4 + 1 = 14.Example 2:
Input: nums = [-5,-3,-3,-2,7,1], multipliers = [-10,-5,3,4,6]
Output: 102
Explanation: An optimal solution is as follows:
- Choose from the start, [-5,-3,-3,-2,7,1], adding -5 * -10 = 50 to the score.
- Choose from the start, [-3,-3,-2,7,1], adding -3 * -5 = 15 to the score.
- Choose from the start, [-3,-2,7,1], adding -3 * 3 = -9 to the score.
- Choose from the end, [-2,7,1], adding 1 * 4 = 4 to the score.
- Choose from the end, [-2,7], adding 7 * 6 = 42 to the score.
The total score is 50 + 15 - 9 + 4 + 42 = 102.
Constraints:
n == nums.length
m == multipliers.length
1 <= m <= 103
m <= n <= 105
-1000 <= nums[i], multipliers[i] <= 1000
Solution:
class Solution {
int[][] dp = new int [1000][1000];
public int maximumScore(int[] nums, int[] multipliers) {
return helper(nums,multipliers,0,nums.length-1,0);
}
public int helper(int[] a,int[] m,int start, int end, int mindex)
{
if(mindex==m.length) return 0;
if(dp[mindex][start]!=0) return dp[mindex][start];
int val1 = m[mindex]*a[start]+helper(a,m,start+1,end,mindex+1);
int val2 = m[mindex]*a[end]+helper(a,m,start,end-1,mindex+1);
dp[mindex][start]=Math.max(val1,val2);
return dp[mindex][start];
}
}