题解 | 斐波那契数列

import sys
n = int(input())
if n == 1 or n == 2:
    print(1)
    sys.exit()
# 动态规划模板法
dp = [0]*(n+1) # 索引0闲置
dp[1],dp[2] = 1,1
for i in range(3,n+1):
    dp[i] = dp[i-1]+dp[i-2]
print(dp[n])