#include <stdio.h>
//練習問題E
int tri (int n) {
if(n==0) {
return 0;
}
else if(n==1) {
return 0;
}
else if(n==2) {
return 1;
}
else {
return tri(n-1)+tri(n-2)+tri(n-3);
}
}
int main(void) {
int n = 7;
printf("数列Tnについて, n=%dのときの値は%d\n", n
, tri
(n
)); return 0;
}
I2luY2x1ZGUgPHN0ZGlvLmg+Ci8v57e057+S5ZWP6aGMRQoKaW50IHRyaSAoaW50IG4pIHsKCWlmKG49PTApIHsKCQlyZXR1cm4gMDsKCX0KCWVsc2UgaWYobj09MSkgewoJCXJldHVybiAwOwoJfQoJZWxzZSBpZihuPT0yKSB7CgkJcmV0dXJuIDE7Cgl9CgllbHNlIHsKCQlyZXR1cm4gdHJpKG4tMSkrdHJpKG4tMikrdHJpKG4tMyk7Cgl9Cn0KCmludCBtYWluKHZvaWQpIHsKCWludCBuID0gNzsKICAgIHByaW50Zigi5pWw5YiXVG7jgavjgaTjgYTjgaYsIG49JWTjga7jgajjgY3jga7lgKTjga8lZFxuIiwgbiwgdHJpKG4pKTsKCXJldHVybiAwOwp9Cg==