diff --git a/13307130389/assignment13/t1.cpp b/13307130389/assignment13/t1.cpp
new file mode 100644
index 0000000..a0d4c67
--- /dev/null
+++ b/13307130389/assignment13/t1.cpp
@@ -0,0 +1,94 @@
+#include<cstdio>
+#include<cstring>
+#include<iostream>
+#include<cstdlib>
+#include<cmath>
+#include<vector>
+#include<queue>
+
+using namespace std ;
+
+typedef pair<int,int> Edge ;
+
+vector<Edge> e[10005] ;
+
+const int oo = 99999999 ;
+
+int dis[10005] = {} ;
+
+int n , m ;
+int ans = 0 ;
+void SPFA()
+{
+	for(int i = 0 ; i < n ; i ++)
+		dis[i] = oo ;
+	queue<int> q ;
+	q.push(0) ;
+	dis[0] = 0 ;
+	while( !q.empty() )
+	{
+		int u = q.front() ; q.pop() ;
+		for(vector<Edge>::iterator it = e[u].begin() ; it != e[u].end() ; it ++)
+		{
+			int v = it->second , w = it->first ;
+			if( dis[v] > dis[u] + w )
+			{
+				dis[v] = dis[u] + w ;
+				q.push(v) ;
+			}
+		}
+	}
+	
+}
+
+void Bfs()
+{
+	bool inq[10005] = {} ;
+	queue<int> q ;
+	q.push(n-1);
+	while(!q.empty() )
+	{
+		int v = q.front() ; q.pop() ;
+		for(vector<Edge>::iterator it = e[v].begin() ; it != e[v].end() ; it ++)
+		{
+			int u = it->second , w = it->first ;
+			if( dis[u] + w == dis[v] )
+			{
+				ans += w ;
+				if(!inq[u])
+				{
+					q.push(u);
+					inq[u] = true ;
+				}
+			}
+		}
+	}
+}
+
+void addedge(int u , int v , int w )
+{
+	e[u].push_back(make_pair(w,v)) ;
+	e[v].push_back(make_pair(w,u)) ;
+}
+
+int main()
+{
+	freopen("in","r",stdin);
+	freopen("out","w",stdout);
+	
+	scanf("%d %d",&n,&m);
+	
+	for(int i = 1 ; i <= m ; i ++)
+	{
+		int u , v , w ;
+		scanf("%d %d %d",&u,&v,&w);
+		addedge(u,v,w) ;
+	}
+	
+	SPFA() ;
+	Bfs() ;
+	
+	printf("%d",ans<<1);
+	
+	return 0;
+}
diff --git a/13307130389/assignment13/t2.cpp b/13307130389/assignment13/t2.cpp
new file mode 100644
index 0000000..06ddefc
--- /dev/null
+++ b/13307130389/assignment13/t2.cpp
@@ -0,0 +1,63 @@
+#include<cstdio>
+#include<cstring>
+#include<iostream>
+#include<cstdlib>
+#include<string>
+#include<algorithm>
+#include<map>
+#include<set>
+#include<vector>
+#include<sstream>
+
+using namespace std ;
+
+int n , k ;
+int fa[50005] = {} , tag[50005] = {} ;
+
+int find( int x )
+{
+        if( fa[x] == x ) return x ;
+        int t = fa[x] ;
+        fa[x] = find(fa[x]) ;
+        tag[x] = (tag[x] + tag[t])%3 ;
+        return fa[x];
+}
+
+void merge(int d , int x ,int y )
+{
+        int fx = find(x) ;
+        int fy = find(y) ;
+        fa[fy] = fx ;
+        tag[fy] = (tag[x]-tag[y]+d-1+3)%3 ;
+}
+
+int main()
+{
+        int ans = 0 ;
+        scanf("%d %d",&n,&k);
+        for(int i = 1 ; i <= n ; i ++)
+        {
+                tag[i] = 0 ;
+                fa[i] = i ;
+        }
+        
+        for(int i = 1 ; i <= k ; i ++)
+        {
+                int d , x , y ;
+                scanf("%d %d %d",&d,&x,&y) ;
+                if( x > n || y > n || (x==y&&d!=1) )
+                {
+                        ans ++ ;
+                        continue ;
+                }
+                int fx = find(x) , fy = find(y) ;
+                if( fx == fy )
+                {
+                        if( (tag[y]-tag[x]+3)%3 != d - 1 ) ans ++ ;
+                }
+                else merge(d,x,y);
+        }
+        printf("%d",ans);
+        return 0;
+}
+
diff --git a/13307130389/assignment13/t3.cpp b/13307130389/assignment13/t3.cpp
new file mode 100644
index 0000000..98e0e24
--- /dev/null
+++ b/13307130389/assignment13/t3.cpp
@@ -0,0 +1,66 @@
+#include<cstdio>
+#include<cstring>
+#include<iostream>
+#include<cstdlib>
+#include<string>
+#include<algorithm>
+#include<map>
+#include<set>
+#include<vector>
+#include<sstream>
+#include<cmath>
+
+using namespace std ;
+const double oo = 99999999 ;
+double dis[505] = {} ;
+bool vis[505] = {} ;
+double nd[505][2] = {} ;
+double res[505] = {} ;
+int rescnt = 0 ;
+int s , n ;
+
+double dist( int x , int y )
+{
+        return sqrt( (nd[x][0]-nd[y][0])*(nd[x][0]-nd[y][0])+(nd[x][1]-nd[y][1])*(nd[x][1]-nd[y][1]) ) ;
+}
+
+int main()
+{
+        int T ;
+        scanf("%d",&T);
+        while(T --)
+        {
+                memset(vis,false,sizeof(vis)) ;
+                rescnt = 0 ;
+                scanf("%d %d",&s,&n) ;
+                for(int i = 1 ; i <= n ; i ++)
+                        scanf("%lf %lf",&nd[i][0],&nd[i][1]) ;
+                for(int i = 1 ; i <= n ; i ++)
+                        dis[i] = oo ;
+                
+                dis[1] = 0 ; vis[1] = true ;
+                int next = 1 ;
+                for(int i = 1 ; i < n ; i ++)
+                {
+                        double mindis = oo ;
+                        for( int j = 1 ; j <= n ; j ++ ) if( j != i && !vis[j] )
+                                if( dis[j] > dist(next,j) )
+                                {
+                                        dis[j] = dist(next,j) ;
+                                }
+                        vis[next] = true ;
+                        for( int j = 1 ; j <= n ; j ++ ) if( !vis[j] )
+                                if( dis[j] < mindis )
+                                {
+                                        mindis = dis[j] ;
+                                        next = j ;
+                                }
+                        res[++ rescnt] = mindis ;
+                }
+                sort( res + 1 , res + n ) ;
+                printf("%.2f\n",res[n-s]);
+         }
+         
+        return 0;
+}
+