diff --git "a/210920142/chapter1/\347\254\254\344\270\200\347\253\240\344\270\212\346\234\272\351\242\230" "b/210920142/chapter1/\347\254\254\344\270\200\347\253\240\344\270\212\346\234\272\351\242\230"
new file mode 100644
index 0000000000000000000000000000000000000000..ddfd551f1904946c39c3741cb6454f1f7b460896
--- /dev/null
+++ "b/210920142/chapter1/\347\254\254\344\270\200\347\253\240\344\270\212\346\234\272\351\242\230"
@@ -0,0 +1,50 @@
+#include<stido.h>
+#include<time.h>
+#include<math.h>
+
+long add1(long n)
+{
+    long i, sum = 0;
+    for (i = 1;i < = n;i++)
+      sum+=i;
+    return sum;
+}
+void AddTime1(long n)
+{
+    clock_t t;
+    long sum;
+    t = clock();
+    sum = add1(n);
+    t = clock() - t;
+    printf("方法1：\n");
+    printf("  结果：1~%d之和:%1d\n",n,sum);
+    printf("  用时: % 1f秒\n",((float)t)/CLOCKS_PER_SES);
+}
+long add2(long n)
+{
+    return n * (n+1)/2;
+
+}
+void AddTime2(long n)
+{
+    clock_t t;
+    long sum;
+    t = clock();
+    sum = add1(n);
+    t = clock() - t;
+    printf("方法2：\n");
+    printf("  结果：1~%d之和:%1d\n",n,sum);
+    printf("  用时: % 1f秒\n",((float)t)/CLOCKS_PER_SES);
+}
+int main()
+{
+    int n;
+    printf("n(大于1000000）:");
+    scanf("% d",&n);
+    if(n<1000000)
+    return 0;
+    AddTime1(n);
+    AddTime2(n);
+    return 1;
+
+}
\ No newline at end of file