๐ ๅๆ Offer 10- II. ้่่ทณๅฐ้ถ้ฎ้ข
2022ๅนด10ๆ10ๆฅ
- algorithm
๐ ๅๆ Offer 10- II. ้่่ทณๅฐ้ถ้ฎ้ข
้พๅบฆ: ๐
้ฎ้ขๆ่ฟฐ
่งฃๆณ
class Solution {
public int numWays(int n) {
// ๆ่ทฏ๏ผ
// ๅพๅบๅ
ฌๅผ f(n) = f(n - 1) + f(n - 2)
// f[0] = 1
// f[1] = 1
// f[2] = 2
if(n == 0) {
return 1;
}
if(n == 1) {
return 1;
}
long a = 1;
long b = 1;
long c = -1;
for(int i = 2; i <= n; i ++) {
c = (a + b) % 1000000007;
a = b;
b = c;
}
return (int)c;
}
}