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Data Structure · Q210

Dynamic Programming in Data Structures

Programming · Data Structure · question 210

Q210

What is the space complexity of the following dynamic programming implementation to find the longest palindromic subsequence where the length of the string is n? #include #include int max_num(int a, int b) if(a > b) return a; return b; int lps(char *str1) int i,j,len; len = strlen(str1); char str2[len + 1]; strcpy(str2, str1); strrev(str2); int arr[len + 1][len + 1]; for(i = 0; i <= len; i++) arr[i][0] = 0; for(i = 0; i <= len; i++) arr[0][i] = 0; for(i = 1; i <= len; i++) for(j = 1; j <= len; j++) if(str1[i-1] == str2[j - 1]) arr[i][j] = 1 + arr[i - 1][j - 1]; else arr[i][j] = max_num(arr[i - 1][j], arr[i][j - 1]); return arr[len][len]; int main() char str1[] = "ababcdabba"; int ans = lps(str1); printf("%d",ans); return 0;

A.
O(n)
B.
O(1)
C.
O(n2)
Answer
D.
O(2)

Answer: Option C

Solution

Answer: Option C
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