Description
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For a string S, let’s define a function F(S) as the minimum number of blocks consisting of consecutive identical characters in S. In other words, F(S) is equal to 1 plus the number of valid indices i such that Si ≠ Si+1.
You are given two strings A and B with lengths N and M respectively. You should merge these two strings into one string C with length N+M. Specifically, each character of C should come either from A or B; all characters from A should be in the same relative order in C as in A and all characters from B should be in the same relative order in C as in B.
Compute the minimum possible value of F(C).
Input
The first line of the input contains a single integer T denoting the number of test cases. The description of T test cases follows.
The first line of each test case contains two space-separated integers N and M.
The second line contains a single string A with length N.
The third line contains a single string B with length M.
Output
For each test case, print a single line containing one integer — the minimum possible value of F(C).
Constraints
1 ≤ T ≤ 100
1 ≤ N, M ≤ 5,000
1 ≤ sum of N in all test cases ≤ 5,000
1 ≤ sum of M in all test cases ≤ 5,000
strings A, B consist only of lowercase English letters
Example Input
Example Output
题意
对于字符串 S,定义函数 F(S) 为:最少可以将 S 划分为几个连续的子串,使得每个子串仅包含相同的字符。换句话说,F(S) 等于 1 加上满足 Si ≠ Si+1 的合法下标 i 的数量。
给定两个字符串 A 和 B,长度分别为 N 和 M。你需要将这两个字符串合并成一个长度为 N + M 的字符串 C。C 的每个字符要么来源于 A,要么来源于 B,且来源于 A 的字符的相对顺序应当与在 A 中一致,来源于 B 的字符亦然。
请求出 F(C) 最小可能的值。
思路
unique 以后直接做 LCS 即可。
AC 代码