2024-07-06
2582. Pass the Pillow
There are n people standing in a line labeled from 1 to n. The first person
in the line is holding a pillow initially. Every second, the person holding
the pillow passes it to the next person standing in the line. Once the pillow
reaches the end of the line, the direction changes, and people continue
passing the pillow in the opposite direction.
For example, once the pillow reaches the nth person they pass it to the n
- 1th person, then to the n - 2th person and so on.
Given the two positive integers n and time, return the index of the person
holding the pillow after time seconds.
100%的是用暴力解 - -
這其實是數學問題
走一趟要 n-1 秒
走到底折返
所以先 time / (n-1) 看可以走完奇數趟還偶數趟
奇數反走 偶數正走
然後 time % (n-1) 看要多走幾格
int passThePillow(int n, int time) {
int dir = (time / (n - 1)) % 2;
int pos = time % (n - 1);
if (dir) return n - pos;
else return pos + 1;
}