Was solving this Cses problem from graph section.I came up with a dp approach for this but getting wrong answer on three testcases.Can anyone help me in where i am going wrong. Here is my submission

my solution 210657479 passes by using a bitset but will give a tle if i use vector...cant figure out the time complexity of reset function

The problem is not monster itself but problem name is....Can anyone tell me why i am getting tle...i am not able to figure out the time complexity of my solution.207893184

Can anyone help me with my last submission. Approach-> 1)Lets take any two strings(say s1 and s2). 2)Now create a string ans from s1 and s2 by taking first character from s1 and then s2 and then repeat. At last we have size of our string ans=4*n. 3)Now i will pair the consecutive same number in the ans string. 4)Now if size of ans is less than or equal to 3*n then it will be my ans otherwise i will create my ans string from s2 and s3,then check for it and lastly check for s1 and s3. Note-> A number can only be paired once. Thanks in advance