1014. Best Sightseeing Pair
package LeetCode_1014 /** * 1014. Best Sightseeing Pair * https://leetcode.com/problems/best-sightseeing-pair/ * Given an array A of positive integers, A[i] represents the value of the i-th sightseeing spot, * and two sightseeing spots i and j have distance j - i between them. The score of a pair (i < j) of sightseeing spots is (A[i] + A[j] + i - j) : the sum of the values of the sightseeing spots, minus the distance between them. Return the maximum score of a pair of sightseeing spots. Example 1: Input: [8,1,5,2,6] Output: 11 Explanation: i = 0, j = 2, A[i] + A[j] + i - j = 8 + 5 + 0 - 2 = 11 Note: 1. 2 <= A.length <= 50000 2. 1 <= A[i] <= 1000 * */ class Solution { /* * solution: by rule: A[i] + A[j] + i - j, change into: (A[i]+i)+(A[j]-j), * so we need to get: max(A[i]+i) and max(A[j]-j), * Time:O(n), Space:(1) * */ fun maxScoreSightseeingPair(A: IntArray): Int { var max = Int.MIN_VALUE //max A[i]+i var maxI = Int.MIN_VALUE //max A[j]-j var maxJ = Int.MIN_VALUE val n = A.size for (i in 0 until n - 1) { if (A[i] + i > maxI) { maxI = A[i] + i //if maxI got the new value, because j depend on i, need reset maxJ maxJ = Int.MIN_VALUE } //because i < j, set j=i+1 val j = i + 1 maxJ = Math.max(maxJ, A[j] - j) max = Math.max(max, maxI + maxJ) } return max } }