Merge branch 'master' of github.com:youngyangyang04/leetcode-master

problems/1971.寻找图中是否存在路径.md

@@ -284,6 +284,48 @@ var validPath = function(n, edges, source, destination) {
 };
 ```
 
+### Go
+
+```go
+func validPath(n int, edges [][]int, source int, destination int) bool {
+	n = 200005
+	father := make([]int, n)
+	// 并查集初始化
+	for i := 0; i < n; i++ {
+		father[i] = i
+	}
+
+	var find func(u int) int // 并查集里寻根的过程
+	find = func(u int) int {
+		// 如果根就是自己，直接返回
+		// 如果根不是自己，就根据数组下标一层一层向下找
+		if u == father[u] {
+			return u
+		}
+		return find(father[u])
+	}
+
+	var join func(u, v int) // 将 v->u 这条边加入并查集
+	join = func(u, v int) {
+		u = find(u)
+		v = find(v)
+		if u == v {
+			return
+		}
+		father[v] = u
+	}
+
+	for i := 0; i < len(edges); i++ {
+		join(edges[i][0], edges[i][1])
+	}
+
+	source = find(source)
+	destination = find(destination)
+	return source == destination
+}
+
+```
+
 <p align="center">
 <a href="https://programmercarl.com/other/kstar.html" target="_blank">
   <img src="../pics/网站星球宣传海报.jpg" width="1000"/>

problems/kama54.替换数字.md

@@ -142,7 +142,7 @@ for (int i = 0; i < a.size(); i++) {
 ### C：
 
 ### Java：
-
+解法一
 ```java
 import java.util.Scanner;
 
@@ -160,6 +160,42 @@ class Main {
     }
 }
 ```
+解法二
+```java
+// 为了还原题目本意，先把原数组复制到扩展长度后的新数组，然后不再使用原数组、原地对新数组进行操作。
+import java.util.*;
+
+public class Main {
+    public static void main(String[] args) {
+        Scanner sc = new Scanner(System.in);
+        String s = sc.next();
+        int len = s.length();
+        for (int i = 0; i < s.length(); i++) {
+            if (s.charAt(i) >= 0 && s.charAt(i) <= '9') {
+                len += 5;
+            }
+        }
+        
+        char[] ret = new char[len];
+        for (int i = 0; i < s.length(); i++) {
+            ret[i] = s.charAt(i);
+        }
+        for (int i = s.length() - 1, j = len - 1; i >= 0; i--) {
+            if ('0' <= ret[i] && ret[i] <= '9') {
+                ret[j--] = 'r';
+                ret[j--] = 'e';
+                ret[j--] = 'b';
+                ret[j--] = 'm';
+                ret[j--] = 'u';
+                ret[j--] = 'n';
+            } else {
+                ret[j--] = ret[i];
+            }
+        }
+        System.out.println(ret);
+    }
+}
+```
 
 ### Go：
 ````go