feat: update solutions to lc problems: No.2278,2279 (#3377)

* No.2278.Percentage of Letter in String
* No.2279.Maximum Bags With Full Capacity of Rocks

Author: yanglbme

solution/2200-2299/2278.Percentage of Letter in String/README.md

@@ -55,7 +55,11 @@ tags:
 
 <!-- solution:start -->
 
-### 方法一
+### 方法一：计数
+
+我们可以遍历字符串 $\textit{s}$，统计其中等于 $\textit{letter}$ 的字符的个数，然后根据公式 $\textit{count} \times 100 \, / \, \textit{len}(\textit{s})$ 计算百分比。
+
+时间复杂度 $O(n)$，其中 $n$ 为字符串 $\textit{s}$ 的长度。空间复杂度 $O(1)$。
 
 <!-- tabs:start -->
 
@@ -89,9 +93,7 @@ class Solution {
 class Solution {
 public:
     int percentageLetter(string s, char letter) {
-        int cnt = 0;
-        for (char& c : s) cnt += c == letter;
-        return cnt * 100 / s.size();
+        return 100 * ranges::count(s, letter) / s.size();
     }
 };
 ```
@@ -100,26 +102,16 @@ public:
 
 ```go
 func percentageLetter(s string, letter byte) int {
-	cnt := 0
-	for i := range s {
-		if s[i] == letter {
-			cnt++
-		}
-	}
-	return cnt * 100 / len(s)
+	return strings.Count(s, string(letter)) * 100 / len(s)
 }
 ```
 
 #### TypeScript
 
 ```ts
 function percentageLetter(s: string, letter: string): number {
-    let count = 0;
-    let total = s.length;
-    for (let i of s) {
-        if (i === letter) count++;
-    }
-    return Math.floor((count / total) * 100);
+    const count = s.split('').filter(c => c === letter).length;
+    return Math.floor((100 * count) / s.length);
 }
 ```
 
@@ -128,13 +120,8 @@ function percentageLetter(s: string, letter: string): number {
 ```rust
 impl Solution {
     pub fn percentage_letter(s: String, letter: char) -> i32 {
-        let mut count = 0;
-        for c in s.chars() {
-            if c == letter {
-                count += 1;
-            }
-        }
-        ((count * 100) / s.len()) as i32
+        let count = s.chars().filter(|&c| c == letter).count();
+        (100 * count as i32 / s.len() as i32) as i32
     }
 }
 ```

solution/2200-2299/2278.Percentage of Letter in String/README_EN.md

@@ -53,7 +53,11 @@ The percentage of characters in s that equal the letter 'k' is 0%, so we
 
 <!-- solution:start -->
 
-### Solution 1
+### Solution 1: Counting
+
+We can traverse the string $\textit{s}$ and count the number of characters that are equal to $\textit{letter}$. Then, we calculate the percentage using the formula $\textit{count} \times 100 \, / \, \textit{len}(\textit{s})$.
+
+Time complexity is $O(n)$, where $n$ is the length of the string $\textit{s}$. Space complexity is $O(1)$.
 
 <!-- tabs:start -->
 
@@ -87,9 +91,7 @@ class Solution {
 class Solution {
 public:
     int percentageLetter(string s, char letter) {
-        int cnt = 0;
-        for (char& c : s) cnt += c == letter;
-        return cnt * 100 / s.size();
+        return 100 * ranges::count(s, letter) / s.size();
     }
 };
 ```
@@ -98,26 +100,16 @@ public:
 
 ```go
 func percentageLetter(s string, letter byte) int {
-	cnt := 0
-	for i := range s {
-		if s[i] == letter {
-			cnt++
-		}
-	}
-	return cnt * 100 / len(s)
+	return strings.Count(s, string(letter)) * 100 / len(s)
 }
 ```
 
 #### TypeScript
 
 ```ts
 function percentageLetter(s: string, letter: string): number {
-    let count = 0;
-    let total = s.length;
-    for (let i of s) {
-        if (i === letter) count++;
-    }
-    return Math.floor((count / total) * 100);
+    const count = s.split('').filter(c => c === letter).length;
+    return Math.floor((100 * count) / s.length);
 }
 ```
 
@@ -126,13 +118,8 @@ function percentageLetter(s: string, letter: string): number {
 ```rust
 impl Solution {
     pub fn percentage_letter(s: String, letter: char) -> i32 {
-        let mut count = 0;
-        for c in s.chars() {
-            if c == letter {
-                count += 1;
-            }
-        }
-        ((count * 100) / s.len()) as i32
+        let count = s.chars().filter(|&c| c == letter).count();
+        (100 * count as i32 / s.len() as i32) as i32
     }
 }
 ```

solution/2200-2299/2278.Percentage of Letter in String/Solution.cpp

@@ -1,8 +1,6 @@
 class Solution {
 public:
     int percentageLetter(string s, char letter) {
-        int cnt = 0;
-        for (char& c : s) cnt += c == letter;
-        return cnt * 100 / s.size();
+        return 100 * ranges::count(s, letter) / s.size();
     }
-};
+};

solution/2200-2299/2278.Percentage of Letter in String/Solution.go

@@ -1,9 +1,3 @@
 func percentageLetter(s string, letter byte) int {
-	cnt := 0
-	for i := range s {
-		if s[i] == letter {
-			cnt++
-		}
-	}
-	return cnt * 100 / len(s)
-}
+	return strings.Count(s, string(letter)) * 100 / len(s)
+}

solution/2200-2299/2278.Percentage of Letter in String/Solution.rs

@@ -1,11 +1,6 @@
 impl Solution {
     pub fn percentage_letter(s: String, letter: char) -> i32 {
-        let mut count = 0;
-        for c in s.chars() {
-            if c == letter {
-                count += 1;
-            }
-        }
-        ((count * 100) / s.len()) as i32
+        let count = s.chars().filter(|&c| c == letter).count();
+        (100 * count as i32 / s.len() as i32) as i32
     }
 }

solution/2200-2299/2278.Percentage of Letter in String/Solution.ts

@@ -1,8 +1,4 @@
 function percentageLetter(s: string, letter: string): number {
-    let count = 0;
-    let total = s.length;
-    for (let i of s) {
-        if (i === letter) count++;
-    }
-    return Math.floor((count / total) * 100);
+    const count = s.split('').filter(c => c === letter).length;
+    return Math.floor((100 * count) / s.length);
 }

solution/2200-2299/2279.Maximum Bags With Full Capacity of Rocks/README.md

@@ -74,6 +74,10 @@ tags:
 
 ### 方法一：排序 + 贪心
 
+我们首先将每个背包的剩余容量计算出来，然后对剩余容量进行排序，接着我们从小到大遍历剩余容量，将额外的石头放入背包中，直到额外的石头用完或者背包的剩余容量用完为止，返回此时的背包数量即可。
+
+时间复杂度 $O(n \times \log n)$，空间复杂度 $O(\log n)$。其中 $n$ 为背包的数量。
+
 <!-- tabs:start -->
 
 #### Python3
@@ -83,37 +87,33 @@ class Solution:
     def maximumBags(
         self, capacity: List[int], rocks: List[int], additionalRocks: int
     ) -> int:
-        d = [a - b for a, b in zip(capacity, rocks)]
-        d.sort()
-        ans = 0
-        for v in d:
-            if v <= additionalRocks:
-                ans += 1
-                additionalRocks -= v
-        return ans
+        for i, x in enumerate(rocks):
+            capacity[i] -= x
+        capacity.sort()
+        for i, x in enumerate(capacity):
+            additionalRocks -= x
+            if additionalRocks < 0:
+                return i
+        return len(capacity)
 ```
 
 #### Java
 
 ```java
 class Solution {
     public int maximumBags(int[] capacity, int[] rocks, int additionalRocks) {
-        int n = capacity.length;
-        int[] d = new int[n];
+        int n = rocks.length;
         for (int i = 0; i < n; ++i) {
-            d[i] = capacity[i] - rocks[i];
+            capacity[i] -= rocks[i];
         }
-        Arrays.sort(d);
-        int ans = 0;
-        for (int v : d) {
-            if (v <= additionalRocks) {
-                ++ans;
-                additionalRocks -= v;
-            } else {
-                break;
+        Arrays.sort(capacity);
+        for (int i = 0; i < n; ++i) {
+            additionalRocks -= capacity[i];
+            if (additionalRocks < 0) {
+                return i;
             }
         }
-        return ans;
+        return n;
     }
 }
 ```
@@ -124,17 +124,18 @@ class Solution {
 class Solution {
 public:
     int maximumBags(vector<int>& capacity, vector<int>& rocks, int additionalRocks) {
-        int n = capacity.size();
-        vector<int> d(n);
-        for (int i = 0; i < n; ++i) d[i] = capacity[i] - rocks[i];
-        sort(d.begin(), d.end());
-        int ans = 0;
-        for (int& v : d) {
-            if (v > additionalRocks) break;
-            ++ans;
-            additionalRocks -= v;
+        int n = rocks.size();
+        for (int i = 0; i < n; ++i) {
+            capacity[i] -= rocks[i];
         }
-        return ans;
+        ranges::sort(capacity);
+        for (int i = 0; i < n; ++i) {
+            additionalRocks -= capacity[i];
+            if (additionalRocks < 0) {
+                return i;
+            }
+        }
+        return n;
     }
 };
 ```
@@ -143,58 +144,55 @@ public:
 
 ```go
 func maximumBags(capacity []int, rocks []int, additionalRocks int) int {
-	n := len(capacity)
-	d := make([]int, n)
-	for i, v := range capacity {
-		d[i] = v - rocks[i]
+	for i, x := range rocks {
+		capacity[i] -= x
 	}
-	sort.Ints(d)
-	ans := 0
-	for _, v := range d {
-		if v > additionalRocks {
-			break
+	sort.Ints(capacity)
+	for i, x := range capacity {
+		additionalRocks -= x
+		if additionalRocks < 0 {
+			return i
 		}
-		ans++
-		additionalRocks -= v
 	}
-	return ans
+	return len(capacity)
 }
 ```
 
 #### TypeScript
 
 ```ts
 function maximumBags(capacity: number[], rocks: number[], additionalRocks: number): number {
-    const n = capacity.length;
-    const diffs = capacity.map((c, i) => c - rocks[i]);
-    diffs.sort((a, b) => a - b);
-    let ans = 0;
-    for (let i = 0; i < n && (diffs[i] === 0 || diffs[i] <= additionalRocks); i++) {
-        ans++;
-        additionalRocks -= diffs[i];
+    const n = rocks.length;
+    for (let i = 0; i < n; ++i) {
+        capacity[i] -= rocks[i];
+    }
+    capacity.sort((a, b) => a - b);
+    for (let i = 0; i < n; ++i) {
+        additionalRocks -= capacity[i];
+        if (additionalRocks < 0) {
+            return i;
+        }
     }
-    return ans;
+    return n;
 }
 ```
 
 #### Rust
 
 ```rust
 impl Solution {
-    pub fn maximum_bags(capacity: Vec<i32>, rocks: Vec<i32>, mut additional_rocks: i32) -> i32 {
-        let n = capacity.len();
-        let mut diffs = vec![0; n];
-        for i in 0..n {
-            diffs[i] = capacity[i] - rocks[i];
+    pub fn maximum_bags(mut capacity: Vec<i32>, rocks: Vec<i32>, mut additional_rocks: i32) -> i32 {
+        for i in 0..rocks.len() {
+            capacity[i] -= rocks[i];
         }
-        diffs.sort();
-        for i in 0..n {
-            if diffs[i] > additional_rocks {
+        capacity.sort();
+        for i in 0..capacity.len() {
+            additional_rocks -= capacity[i];
+            if additional_rocks < 0 {
                 return i as i32;
             }
-            additional_rocks -= diffs[i];
         }
-        n as i32
+        capacity.len() as i32
     }
 }
 ```