1968B - Prefiquence - CodeForces Solution

t = int(input())
for test in range(t):
    nm = list(map(int,input().split()))
    n = nm[0]
    m = nm[1]
    arr_a = list(input())
    arr_b = list(input())
    p1=0
    p2=0
    ans=0
    while p1<n and p2<m:
        if arr_a[p1]==arr_b[p2]:
            p1+=1
            ans+=1
        p2+=1
    print(ans)