CodeForces - 1000D Yet Another Problem On a Subsequence

题面在这里！

好智障的一个dp啊，一段开头的数字相当于下面要跟多少个数，直接滚动数组dp就行了。。。

#include<bits/stdc++.h>
#define ll long long
using namespace std;
const int N=1005,ha=998244353;inline void ADD(int &x,int y){ x+=y; if(x>=ha) x-=ha;}int f[N],n,a[N];int main(){scanf("%d",&n);for(int i=1;i<=n;i++) scanf("%d",a+i);f[0]=1;for(int i=1,now;i<=n;i++){now=f[0];for(int j=0;j<n;j++) ADD(f[j],f[j+1]);if(a[i]>0&&a[i]+i<=n) ADD(f[a[i]],now);}ADD(f[0],ha-1),printf("%d\n",f[0]);return 0;
}

转载于:https://www.cnblogs.com/JYYHH/p/9251031.html

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