feat: add new solutions to lc problems: No.2894 2896 (#1783)

Author: Ming91

solution/2800-2899/2894.Divisible and Non-divisible Sums Difference/README.md

@@ -100,6 +100,17 @@ class Solution {
 }
 ```
 
+```java
+class Solution {
+    public int differenceOfSums(int n, int m) {
+        int sum = n * (n + 1) / 2;
+        int k = n / m;
+        int nums2 = k * (k + 1) / 2 * m;
+        return sum - nums2 * 2;
+    }
+}
+```
+
 ### **C++**
 
 ```cpp

solution/2800-2899/2894.Divisible and Non-divisible Sums Difference/README_EN.md

@@ -90,6 +90,17 @@ class Solution {
 }
 ```
 
+```java
+class Solution {
+    public int differenceOfSums(int n, int m) {
+        int sum = n * (n + 1) / 2;
+        int k = n / m;
+        int nums2 = k * (k + 1) / 2 * m;
+        return sum - nums2 * 2;
+    }
+}
+```
+
 ### **C++**
 
 ```cpp

solution/2800-2899/2896.Apply Operations to Make Two Strings Equal/README.md

@@ -144,6 +144,36 @@ class Solution {
 }
 ```
 
+```java
+class Solution {
+    public int minOperations(String s1, String s2, int x) {
+        int n = s1.length();
+        int inf = 50_000;
+        int one = inf, two = inf, last = inf;
+        int done = 0;
+        for (int i = 0; i < n; i++) {
+            if (s1.charAt(i) == s2.charAt(i)) {
+                one = Math.min(one, last);
+                last = last + 1;
+                two = two + 1;
+                continue;
+            }
+            if (done < n) {
+                one = Math.min(two + 1, done + x);
+                last = Math.min(two + x, done);
+                done = two = inf;
+                continue;
+            }
+            done = Math.min(one + x, last + 1);
+            two = one;
+            one = last = inf;
+            continue;
+        }
+        return done == inf ? -1 : done;
+    }
+}
+```
+
 ### **C++**
 
 ```cpp

solution/2800-2899/2896.Apply Operations to Make Two Strings Equal/README_EN.md

@@ -134,6 +134,36 @@ class Solution {
 }
 ```
 
+```java
+class Solution {
+    public int minOperations(String s1, String s2, int x) {
+        int n = s1.length();
+        int inf = 50_000;
+        int one = inf, two = inf, last = inf;
+        int done = 0;
+        for (int i = 0; i < n; i++) {
+            if (s1.charAt(i) == s2.charAt(i)) {
+                one = Math.min(one, last);
+                last = last + 1;
+                two = two + 1;
+                continue;
+            }
+            if (done < n) {
+                one = Math.min(two + 1, done + x);
+                last = Math.min(two + x, done);
+                done = two = inf;
+                continue;
+            }
+            done = Math.min(one + x, last + 1);
+            two = one;
+            one = last = inf;
+            continue;
+        }
+        return done == inf ? -1 : done;
+    }
+}
+```
+
 ### **C++**
 
 ```cpp