diff --git a/code_graph_2021.cpp b/code_graph_2021.cpp
index 4a73703..fbd1e83 100644
--- a/code_graph_2021.cpp
+++ b/code_graph_2021.cpp
@@ -1,4 +1,45 @@
 #include <stdio.h>
+#include <stdlib.h>
+#define MAXV 5
+typedef struct {
+    int numVertices, numEdges;
+    char VerticesList[MAXV];
+    int Edge[MAXV][MAXV];
+}MGraph;
+int IsExistEL(MGraph G) {
+    int oddCount = 0;
+    for (int i = 0;i < G.numVertices;i++) {
+        int tmpOdd = 0;
+        for (int j = 0;j < G.numVertices;j++) {
+            tmpOdd += G.Edge[i][j];
+        }
+        if (tmpOdd % 2 == 1) {
+            oddCount++;
+            if (oddCount > 2) {
+                return 0;
+            }
+        }
+    }
+    if (oddCount == 0 || oddCount == 2)return 1;
+    else return 0;
+}
+void setG(MGraph* g, int a[]) {
+    for (int i = 0;i < MAXV * MAXV;i++) {
+        g->Edge[i / 5][i % 5] = a[i];
+    }
+}
 int main() {
-    printf("hello");
+    MGraph G;
+    G.numVertices = 5;
+    int a[] = {
+        1,1,0,0,1,//
+        1,0,1,0,1,//
+        0,1,0,1,1,//
+        0,0,1,0,1,//
+        0,0,0,1,0,//
+    };
+    setG(&G, a);
+    int i = IsExistEL(G);
+    printf("%d", i);
+    return 0;
 }
\ No newline at end of file