大冥神的代码，以后能贴的机会估计就更少了。。。。所以本着有就贴的好习惯，= =。。。。直接贴
#include <bits/stdc++.h>
using LL = long long ;
#define ALL(v) (v).begin(),(v).end()
#define showtime fprintf(stderr,"time = %.15f\n",clock() / (double)CLOCKS_PER_SEC) char str[100][11];
int n,m;
int weight[100]; const int N = 10 * 100 + 5;
int go[N][26],val[N],fail[N],tot; int get_node() {
memset(go[tot],-1,sizeof(go[tot]));
val[tot] = 0;
return tot ++;
} int dp[50 + 1][N],pre[50 + 1][N],pc[50 + 1][N];
std::vector<int> order[50 + 1]; void insert(char *s,int w) {
int u = 0;
for ( ; *s; ++ s) {
int c = *s - 'a';
if (go[u][c] == -1)
go[u][c] = get_node();
u = go[u][c];
}
val[u] += w;
} std::string work() {
tot = 0;
get_node();
for (int i = 0; i < m; ++ i) {
insert(str[i],weight[i]);
}
std::vector<int> vec{0};
fail[0] = -1;
for (int I = 0; I < (int)vec.size(); ++ I) {
int u = vec[I];
for (int c = 0; c < 26; ++ c) {
if (go[u][c] == -1) continue;
int v = go[u][c];
int f = fail[u];
while (f != -1 && go[f][c] == -1) f = fail[f];
fail[v] = f == -1 ? 0 : go[f][c];
vec.push_back(v);
}
}
for (int I = (int)vec.size() - 1; I >= 0; -- I) {
int u = vec[I];
for (int c = 0; c < 26; ++ c) {
int f = u;
while (f != -1 && go[f][c] == -1) f = fail[f];
go[u][c] = f == -1 ? -1 : go[f][c];
}
for (int f = fail[u]; f != -1; f = fail[f]) {
val[u] += val[f];
}
}
memset(dp,-1,sizeof(dp));
memset(pre,-1,sizeof(pre));
dp[0][0] = 0;
for (int i = 0; i <= n; ++ i) {
order[i].clear();
}
order[0].push_back(0);
for (int i = 0; i < n; ++ i) {
for (int u : order[i]) {
for (int c = 0; c < 26; ++ c) {
if (go[u][c] == -1) continue;
int v = go[u][c];
dp[i + 1][v] = std::max(dp[i + 1][v],dp[i][u] + val[v]);
}
}
for (int u : order[i]) {
for (int c = 0; c < 26; ++ c) {
if (go[u][c] == -1) continue;
int v = go[u][c];
if (dp[i + 1][v] == dp[i][u] + val[v] && pre[i + 1][v] == -1) {
pre[i + 1][v] = u;
pc[i + 1][v] = c;
order[i + 1].push_back(v);
}
}
}
} int ai = 0,au = 0;
for (int i = 0; i <= n; ++ i) {
for (int u : order[i]) {
if (dp[i][u] > dp[ai][au]) {
ai = i;
au = u;
}
}
}
std::string ret;
while (ai) {
ret.push_back(pc[ai][au] + 'a');
au = pre[ai][au];
-- ai;
}
std::reverse(ALL(ret));
return ret;
} int main() {
int cas;
scanf("%d",&cas);
while (cas--) {
scanf("%d%d",&n,&m);
for (int i = 0; i < m; ++ i) {
scanf("%s",str[i]);
}
for (int i = 0; i < m; ++ i) {
scanf("%d",weight + i);
}
printf("%s\n",work().c_str());
}
}