题意：给定两个递增数列A和B，构造一个ai <= ci <= bi 的递增数列C，询问满足条件的C的个数。
普通dp会超时，用前缀和优化
n=int(input())
a=list(map(int,input().split()))
b=list(map(int,input().split()))
l=3010
dp=[[0]*l for _ in range(n+1)]
dp[0][0]=1
for i in range(n):
for j in range(l):
if dp[i][j]==0:
continue
dp[i+1][max(j,a[i])]+=dp[i][j]
dp[i+1][b[i]+1]-=dp[i][j]
for j in range(l-1):
dp[i+1][j+1]+=dp[i+1][j]
dp[i+1][j+1]%=998244353
print(sum(dp[-1])%998244353)
标签：前缀,Arrays,Two,int,range,Between,input,dp From： https://www.cnblogs.com/trave11er/p/17552399.html