题解 | #统计每个月兔子的总数#

#include <stdio.h>
int main(int argc, char** argv)
{
    int mon, old = 1, num = 1;
    scanf("%d", &mon);
    for (int i = 3; i <= mon; i++) { num += old; old = num - old; }
    printf("%d\n", num);
    return 0;
}