Educational Codeforces Round 39 F,G

F. Fibonacci String Subsequences

The DP state is set to indicate the number of matches dp[i][j][k]between the string F(i) and the given string. There are two forms of transfer equations: 1. Completely provided by or completely provided by: : dp [ i ] [ j ] [ k ] = dp [ i − 1 ] [ j ] [ k ] ⋅ 2 len [ i − 2 ] dp[i][j][k]=dp[i-1][j][ k] \cdot 2^{len[i-2]}s[j...k]

s[j...k]f(i-1)f(i-2)
f(i-1)
k=n$dp[i][j][k]=dp[i-1][j][k]\cdot 2^{len[i-2]}$
k!=n:$dp[i][j][k]=dp[i-1]\left[j\right]\left[k\right]$
is completelyf(i-2)given by:
j=1:$dp\left[i\right]\left[j\right]\left[k\right]=dp[i-2][j][k]\cdot 2^{len[i-1]}$
j!=1:$dp[i][j][k]=dp[i-2][j][k]$
2.s[j...mid]由f(i-1)提供，s[(mid+1)...k]由f(i-2)提供
$dp\left[i\right]\left[j\right]\left[k\right]={\sum }_{mid=j}^{k-1}dp[i-1][j][mid]\cdot dp[i-2][mid+1[k]$

Code:https://codeforces.com/contest/946/submission/173902552