修改文件结构。

POP/08/Exercise01.c

@@ -0,0 +1,73 @@
+#include <stdio.h>
+#include <time.h>
+#include <stdbool.h>
+
+#define DEAD true
+#define ALIVE false
+
+bool people[40] = {0};
+
+void iteration() {
+    int nowCount = 0, nowPos = 0, nowDead = 0;
+    while (nowDead < 39) {
+        nowCount = 0;
+        while (nowCount < 3) {
+            if (people[nowPos % 40]==ALIVE) {
+                nowCount++;
+            }
+            nowPos++;
+        }
+        people[(nowPos+39)%40] = DEAD;
+        nowDead+=1;
+    }
+    for (nowPos = 0; nowPos < 40; nowPos++) {
+        if (people[nowPos % 40] == ALIVE) {
+            printf("Stand at %d\n", nowPos+1);
+            break;
+        }
+    }
+}
+
+int recursion(int nowDead, int nowPos) {
+    int nowCount=0;
+    if (nowDead == 39) {
+        for (nowPos = 0; nowPos < 40; nowPos++) {
+            if (people[nowPos % 40] == ALIVE) {
+                // printf("Stand at %d\n", nowPos+1);
+                return nowPos;
+            }
+        }
+    }
+    else {
+        while (nowCount < 3) {
+            if (people[nowPos % 40]==ALIVE) {
+                nowCount++;
+            }
+            nowPos++;
+        }
+        people[(nowPos+39)%40] = DEAD;
+        return recursion(nowDead+1, nowPos);
+    }
+}
+
+int main() {
+    int startTime, finishTime;
+    double time;
+    int i = 0;
+    startTime = clock();
+    iteration();
+    finishTime = clock();
+    time = ((double)(finishTime - startTime))/CLOCKS_PER_SEC;
+    printf("Time elapsed: %lfs\n", time);
+
+    for (i = 0; i < 40; i++) {
+        people[i] = ALIVE;
+    }
+
+    startTime = clock();
+    printf("Stand at %d\n",recursion(0,0)+1);
+    finishTime = clock();
+    time = ((double)(finishTime - startTime))/CLOCKS_PER_SEC;
+    printf("Time elapsed: %lfs", time);
+    return 0;
+}