Merge pull request #1038 from 0xff-dev/2516

Add solution and test-cases for problem 2516

Author: 6boris

leetcode/2501-2600/2516.Take-K-of-Each-Character-From-Left-and-Right/README.md

@@ -0,0 +1,33 @@
+# [2516.Take K of Each Character From Left and Right][title]
+
+## Description
+You are given a string `s` consisting of the characters `'a'`, `'b'`, and `'c'` and a non-negative integer `k`. Each minute, you may take either the **leftmost** character of `s`, or the **rightmost** character of `s`.
+
+Return the **minimum** number of minutes needed for you to take **at least** `k` of each character, or return `-1` if it is not possible to take `k` of each character.
+
+**Example 1:**
+
+```
+Input: s = "aabaaaacaabc", k = 2
+Output: 8
+Explanation: 
+Take three characters from the left of s. You now have two 'a' characters, and one 'b' character.
+Take five characters from the right of s. You now have four 'a' characters, two 'b' characters, and two 'c' characters.
+A total of 3 + 5 = 8 minutes is needed.
+It can be proven that 8 is the minimum number of minutes needed.
+```
+
+**Example 2:**
+
+```
+Input: s = "a", k = 1
+Output: -1
+Explanation: It is not possible to take one 'b' or 'c' so return -1.
+```
+
+## 结语
+
+如果你同我一样热爱数据结构、算法、LeetCode，可以关注我 GitHub 上的 LeetCode 题解：[awesome-golang-algorithm][me]
+
+[title]: https://leetcode.com/problems/take-k-of-each-character-from-left-and-right
+[me]: https://github.com/kylesliu/awesome-golang-algorithm

leetcode/2501-2600/2516.Take-K-of-Each-Character-From-Left-and-Right/Solution.go

@@ -1,5 +1,64 @@
 package Solution
 
-func Solution(x bool) bool {
-	return x
+import "sort"
+
+func Solution(s string, k int) int {
+	if k == 0 {
+		return 0
+	}
+	l := len(s)
+	left, right := make([][3]int, l), make([][3]int, l)
+	left[0][s[0]-'a'] = 1
+	for i := 1; i < l; i++ {
+		left[i] = left[i-1]
+		left[i][s[i]-'a']++
+	}
+	right[l-1][s[l-1]-'a'] = 1
+	for i := l - 2; i >= 0; i-- {
+		right[i] = right[i+1]
+		right[i][s[i]-'a']++
+	}
+	ans := -1
+	for i := l - 1; i > 0; i-- {
+		a, b, c := right[i][0], right[i][1], right[i][2]
+		if a >= k && b >= k && c >= k {
+			if ans == -1 || ans > l-i {
+				ans = l - i
+			}
+			continue
+		}
+		idx := sort.Search(i, func(ii int) bool {
+			return left[ii][0]+a >= k && left[ii][1]+b >= k && left[ii][2]+c >= k
+		})
+		if idx == i {
+			continue
+		}
+		diff := l - i + idx + 1
+		if ans == -1 || ans > diff {
+			ans = diff
+		}
+	}
+
+	for i := 0; i < l-1; i++ {
+		a, b, c := left[i][0], left[i][1], left[i][2]
+		if a >= k && b >= k && c >= k {
+			if ans == -1 || ans > i+1 {
+				ans = i + 1
+			}
+			continue
+		}
+		ll := l - i - 1
+		start := i + 1
+		idx := sort.Search(ll, func(ii int) bool {
+			return right[start][0]+a >= k && right[start][1]+b >= k && right[start][2]+c >= k
+		})
+		if idx == ll {
+			continue
+		}
+		diff := i + 1 + l - i
+		if ans == -1 || ans > diff {
+			ans = diff
+		}
+	}
+	return ans
 }

leetcode/2501-2600/2516.Take-K-of-Each-Character-From-Left-and-Right/Solution_test.go

@@ -10,30 +10,30 @@ func TestSolution(t *testing.T) {
 	//	测试用例
 	cases := []struct {
 		name   string
-		inputs bool
-		expect bool
+		s      string
+		k      int
+		expect int
 	}{
-		{"TestCase", true, true},
-		{"TestCase", true, true},
-		{"TestCase", false, false},
+		{"TestCase1", "aabaaaacaabc", 2, 8},
+		{"TestCase2", "a", 1, -1},
 	}
 
 	//	开始测试
 	for i, c := range cases {
 		t.Run(c.name+" "+strconv.Itoa(i), func(t *testing.T) {
-			got := Solution(c.inputs)
+			got := Solution(c.s, c.k)
 			if !reflect.DeepEqual(got, c.expect) {
-				t.Fatalf("expected: %v, but got: %v, with inputs: %v",
-					c.expect, got, c.inputs)
+				t.Fatalf("expected: %v, but got: %v, with inputs: %v %v",
+					c.expect, got, c.s, c.k)
 			}
 		})
 	}
 }
 
-//	压力测试
+// 压力测试
 func BenchmarkSolution(b *testing.B) {
 }
 
-//	使用案列
+// 使用案列
 func ExampleSolution() {
 }