def solve(N,K,A): diff = [A[0] for i in range(N)] S = A[0] for i in range(1,N): diff[i] = S - A[i] if diff[i] < 0: return 0 S += A[i] diff.append(0) dp = [{} for i in range(N-1)] stack = [(N-2,dp_S) for dp_S in range(10*K+10)] while stack: i,j = stack.pop() if j in dp[i]: continue dp[i][j] = [0 for k in range(6*K+2)] if not i: continue if diff[i]: stack.append((i-1,(j+diff[i+1]-2*K-1+diff[i])//2-diff[i]+2*K+1)) if diff[i]<=1: for k in range(-2,1): stack.append((i-1,(j+diff[i+1]-2*K-1+k)//2+2*K+1)) stack.append((i-1,(j+diff[i+1]-2*K-1-diff[i])//2+2*K+1)) cum = [{sum:[0 for minus in range(6*K+2)] for sum in dp[i]} for i in range(N-1)] mod = 998244353 for minus in range(6*K+2): for sum in dp[0]: dp_S = sum - minus real_S = diff[1] + dp_S - 2*K - 1 first = diff[0] - minus if first==real_S and -K<=first<=K: dp[0][sum][minus] = 1 for sum in dp[0]: cum[0][sum][0] = dp[0][sum][0] for minus in range(1,6*K+2): cum[0][sum][minus] = dp[0][sum][minus] + cum[0][sum][minus-1] cum[0][sum][minus] %= mod for i in range(1,N-1): for minus in range(6*K+2): for sum in dp[i]: dp_S = sum - minus real_S = dp_S + diff[i+1] - 2*K - 1 if diff[i]: L = max((real_S+minus+diff[i]+1)//2,-K+minus+diff[i]) R = min((real_S+minus+diff[i])//2,K+minus+diff[i]) if L==R: pre_dp_S = L - diff[i] + 2*K + 1 dp[i][sum][minus] += dp[i-1][pre_dp_S][0] dp[i][sum][minus] %= mod if minus%2==diff[i] and real_S%2==0 and -K<=real_S//2<=K: pre_minus_L = max(0,minus//2+1+diff[i]) pre_minus_R = min(6*K+1,minus//2+3*K+diff[i]) if pre_minus_L<=pre_minus_R: pre_sum = real_S//2+minus//2+2*K+1 dp[i][sum][minus] += cum[i-1][pre_sum][pre_minus_R] - cum[i-1][pre_sum][pre_minus_L] + dp[i-1][pre_sum][pre_minus_L] dp[i][sum][minus] %= mod if diff[i]<=1 and (real_S+minus-diff[i])%2==0: m = max(0,-K+minus-diff[i]-(real_S+minus-diff[i])//2) M = min((minus-diff[i])//2,K+minus-diff[i]-(real_S+minus-diff[i])//2) pre_minus_L = max(0,m+diff[i]) pre_minus_R = min(6*K+1,M+diff[i]) if pre_minus_R>=pre_minus_L: pre_sum = (real_S+minus-diff[i])//2+2*K+1 dp[i][sum][minus] += cum[i-1][pre_sum][pre_minus_R] - cum[i-1][pre_sum][pre_minus_L] + dp[i-1][pre_sum][pre_minus_L] dp[i][sum][minus] %= mod for sum in cum[i]: cum[i][sum][0] = dp[i][sum][0] for minus in range(1,6*K+2): cum[i][sum][minus] = cum[i][sum][minus-1] + dp[i][sum][minus] cum[i][sum][minus] %= mod res = 0 for real_S in range(-N*K,N*K+1): minus = 0 i = N - 1 if diff[i]: L = max((real_S+minus+diff[i]+1)//2,-K+minus+diff[i]) R = min((real_S+minus+diff[i])//2,K+minus+diff[i]) if L==R: pre_dp_S = L - diff[i] + 2*K + 1 res += dp[i-1][pre_dp_S][0] res %= mod if minus%2==diff[i] and real_S%2==0 and -K<=real_S//2<=K: pre_minus_L = max(0,minus//2+1+diff[i]) pre_minus_R = min(6*K+1,minus//2+3*K+diff[i]) if pre_minus_L<=pre_minus_R: pre_sum = real_S//2+minus//2+2*K+1 res += cum[i-1][pre_sum][pre_minus_R] - cum[i-1][pre_sum][pre_minus_L] + dp[i-1][pre_sum][pre_minus_L] res %= mod if diff[i]<=1 and (real_S+minus-diff[i])%2==0: m = max(0,-K+minus-diff[i]-(real_S+minus-diff[i])//2) M = min((minus-diff[i])//2,K+minus-diff[i]-(real_S+minus-diff[i])//2) pre_minus_L = max(0,m+diff[i]) pre_minus_R = min(6*K+1,M+diff[i]) if pre_minus_R>=pre_minus_L: pre_sum = (real_S+minus-diff[i])//2+2*K+1 res += cum[i-1][pre_sum][pre_minus_R] - cum[i-1][pre_sum][pre_minus_L] + dp[i-1][pre_sum][pre_minus_L] res %= mod return res N,K = map(int,input().split()) A = list(map(int,input().split())) print(solve(N,K,A))