set jdk to 1.7

Author: shijiebei2009

pom.xml

@@ -14,8 +14,8 @@
                 <artifactId>maven-compiler-plugin</artifactId>
                 <version>2.5.1</version>
                 <configuration>
-                    <source>1.8</source>
-                    <target>1.8</target>
+                    <source>1.7</source>
+                    <target>1.7</target>
                 </configuration>
             </plugin>
         </plugins>

src/main/java/cn/codepub/algorithms/graph/Kruskal.java

@@ -4,7 +4,6 @@
 import org.junit.Test;
 
 import java.util.*;
-import java.util.stream.Collectors;
 
 /**
  * <p>
@@ -89,7 +88,8 @@ public int compare(Object o1, Object o2) {
         });
 
         // 加入优先级队列
-        queue.addAll(edgeList.stream().collect(Collectors.toList()));
+        queue.addAll(edgeList);
+        // queue.addAll(edgeList.stream().collect(Collectors.toList()));
         while (!queue.isEmpty()) {
             Edge remove = queue.remove();
             Vertex start = remove.start;//获取起始点