CSES — DP Coin Combination II TLE

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Kaleab_Asfaw's blog

CSES — DP Coin Combination II TLE

By Kaleab_Asfaw, history, 4 years ago, In English

Getting TLE with a python solution for Coin Combination problem in here

I know that python is slow ..., but have seen other python users solving it here

My Code

def solve(n, x, lst):
    dp = []
    for i in range(n+1):
        temp = [1] + [0]*x
        dp.append(temp)

    for i in range(1, n+1):
        for j in range(1, x+1):
            dp[i][j] = (dp[i][j] + dp[i-1][j]) % mod
            if j - lst[i-1] >= 0:
                dp[i][j] = (dp[i][j] + dp[i][j - lst[i-1]]) % mod
    for i in dp: print(i)
    return dp[n][x]

n, x = list(map(int, input().split()))
lst = list(map(int, input().split()))
print(solve(n, x, lst))

...

Creating the dp 2D array is even taking much time. Is there a way it can be optimized?

Thanks for taking your time and reading this!

dp, #dynamic programing, #tle, #optimization

Kaleab_Asfaw
4 years ago
4

Comments (1)

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spookywooky

4 years ago, # |

The dp can be 1 dimensional, let c[] be the coins and x the sum, then dp[x] is the answer:

    dp[0]=1;
    for(int a : c) {
        for(int i=0; i+a<=x; i++) {
            dp[i+a]+=dp[i];
            dp[i+a]%=MOD;
        }
    }

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