added problem 2542

Author: SHA65536

problems/problem2542/max_score_subseq.go

@@ -0,0 +1,73 @@
+package problem2542
+
+import (
+	"container/heap"
+	"sort"
+)
+
+/*
+You are given two 0-indexed integer arrays nums1 and nums2 of equal length n and a positive integer k.
+You must choose a subsequence of indices from nums1 of length k.
+For chosen indices i0, i1, ..., ik - 1, your score is defined as:
+    The sum of the selected elements from nums1 multiplied with the minimum of the selected elements from nums2.
+    It can defined simply as: (nums1[i0] + nums1[i1] +...+ nums1[ik - 1]) * min(nums2[i0] , nums2[i1], ... ,nums2[ik - 1]).
+Return the maximum possible score.
+A subsequence of indices of an array is a set that can be derived from the set {0, 1, ..., n-1} by deleting some or no elements.
+*/
+
+func maxScore(nums1, nums2 []int, k int) int64 {
+	var res, sum int64
+	var order = make([]int, len(nums1))
+	for i := range order {
+		order[i] = i
+	}
+
+	sort.Slice(order, func(i, j int) bool {
+		return nums2[order[i]] >= nums2[order[j]]
+	})
+
+	var pq = MakeHeap(MinHeap)
+
+	for i := range order {
+		e, s := nums2[order[i]], nums1[order[i]]
+		heap.Push(pq, s)
+		sum += int64(s)
+		if pq.Len() > k {
+			sum -= int64(heap.Pop(pq).(int))
+		}
+		if pq.Len() == k {
+			res = max(res, sum*int64(e))
+		}
+	}
+
+	return res
+}
+
+type Heap struct {
+	Values   []int
+	LessFunc func(int, int) bool
+}
+
+func (h *Heap) Less(i, j int) bool { return h.LessFunc(h.Values[i], h.Values[j]) }
+func (h *Heap) Swap(i, j int)      { h.Values[i], h.Values[j] = h.Values[j], h.Values[i] }
+func (h *Heap) Len() int           { return len(h.Values) }
+func (h *Heap) Peek() int          { return h.Values[0] }
+func (h *Heap) Pop() (v interface{}) {
+	h.Values, v = h.Values[:h.Len()-1], h.Values[h.Len()-1]
+	return v
+}
+func (h *Heap) Push(v interface{}) { h.Values = append(h.Values, v.(int)) }
+
+func MakeHeap(less func(int, int) bool) *Heap {
+	return &Heap{LessFunc: less}
+}
+
+func MaxHeap(i, j int) bool { return i > j }
+func MinHeap(i, j int) bool { return i < j }
+
+func max(a, b int64) int64 {
+	if a > b {
+		return a
+	}
+	return b
+}

problems/problem2542/max_score_subseq_test.go

@@ -0,0 +1,37 @@
+package problem2542
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+type Result struct {
+	Nums1, Nums2 []int
+	K            int
+	Expected     int64
+}
+
+var Results = []Result{
+	{[]int{1, 3, 3, 2}, []int{2, 1, 3, 4}, 3, 12},
+	{[]int{4, 2, 3, 1, 1}, []int{7, 5, 10, 9, 6}, 1, 30},
+}
+
+func TestMaxScoreSubsequence(t *testing.T) {
+	assert := assert.New(t)
+
+	for _, res := range Results {
+		want := res.Expected
+		got := maxScore(res.Nums1, res.Nums2, res.K)
+		assert.Equal(want, got, fmt.Sprintf("%+v", res))
+	}
+}
+
+func BenchmarkMaxScoreSubsequenceh(b *testing.B) {
+	for i := 0; i < b.N; i++ {
+		for _, res := range Results {
+			maxScore(res.Nums1, res.Nums2, res.K)
+		}
+	}
+}

readme.md

@@ -493,6 +493,7 @@ Each problem is in it's own directory, with test files. There are helper package
 | 2477 | [Minimum Fuel Cost to Report to the Capital](https://leetcode.com/problems/minimum-fuel-cost-to-report-to-the-capital) | [My Solution](./problems/problem2477) | ✅ |
 | 2492 | [Minimum Score of a Path Between Two Cities](https://leetcode.com/problems/minimum-score-of-a-path-between-two-cities) | [My Solution](./problems/problem2492) | ✅ |
 | 2512 | [Reward Top K Students](https://leetcode.com/problems/reward-top-k-students) | [My Solution](./problems/problem2512) | ✅ |
+| 2542 | [Maximum Subsequence Score](https://leetcode.com/problems/maximum-subsequence-score) | [My Solution](./problems/problem2542) | ✅ |
 | 2553 | [Separate the Digits in an Array](https://leetcode.com/problems/separate-the-digits-in-an-array) | [My Solution](./problems/problem2553) | ✅ |
 | 2558 | [Take Gifts From the Richest Pile](https://leetcode.com/problems/take-gifts-from-the-richest-pile) | [My Solution](./problems/problem2558) | ✅ |
 | 2562 | [Find the Array Concatenation Value](https://leetcode.com/problems/find-the-array-concatenation-value) | [My Solution](./problems/problem2562) | ✅ |
@@ -511,6 +512,7 @@ Each problem is in it's own directory, with test files. There are helper package
 | 0087 | Needs revision |
 | 1857 | Needs revision |
 | 0879 | Needs revision |
+| 2542 | Needs revision |
 | 1799 | Black magic |