Lesson 8.

08/Exercise02.c

@@ -0,0 +1,43 @@
+#include <stdio.h>
+#include <time.h>
+
+int goDown(int n) {
+    if (n == 1) {
+        return 1;
+    }
+    else if (n == 2) {
+        return 2;
+    }
+    else if (n == 3) {
+        return 4;
+    }
+    else {
+        return goDown(n-1) + goDown(n-2) + goDown(n-3);
+    }
+}
+
+int main() {
+    int n = 0;
+    int i = 0, j = 0;
+    int startTime, finishTime;
+    double time;
+    double timeSum;
+    int ans;
+    for (i = 5; i < 21; i++) {
+        printf("%d: %d\n", i, goDown(i));
+    }
+    for (j = 15; j <=35; j+=10) {
+        printf("n = %d\n", j);
+        for (i = 0; i < 3; i++) {
+            startTime = clock();
+            ans = goDown(j);
+            finishTime = clock();
+            time = ((double)finishTime - startTime) / CLOCKS_PER_SEC;
+            timeSum += time;
+            printf("%.16lf\n", time);
+        }
+        printf("Avg: %lf\n", timeSum/3);
+        timeSum = 0;
+    }
+    return 0;
+}