CodeForces 566 A Matching Names（Trie 匹配LCP和最大）

#include<bits/stdc++.h>
using namespace std;
const int maxnode = 8e5+5;
int ch[maxnode][26], sz;
char str[maxnode];
bool vis[maxnode][2];
int match[maxnode];
vector<int> val[maxnode][2];

void init()
{
sz = 1;
memset(ch[0], 0, sizeof(ch[0]));
}

void Insert(char *s, int id, int v)
{
int u = 0;
int len = strlen(s);
val[u][id].push_back(v);    //最后几个可能一个字符都不匹配，所以一定要在根处也加上
for(int i = 0; i < len; i++)
{
if(ch[u][s[i]-'a'] == 0)
{
memset(ch[sz], 0, sizeof(ch[sz]));
val[sz][id].clear();
ch[u][s[i]-'a'] = sz++;
}
u = ch[u][s[i]-'a'];
val[u][id].push_back(v);
}
}

int dfs(int dep, int u)
{
int ans = 0;
for(int i = 0; i < 26; i++)
if(ch[u][i])    //尽可能深
ans += dfs(dep+1, ch[u][i]);
vector<int> tmp[2];
for(int i = 0; i < 2; i++)
for(int j = 0; j < val[u][i].size(); j++)
if(!vis[val[u][i][j]][i])   //到这一层还没匹配过的具有公共前缀的都可以进行匹配了 已经是最优了
tmp[i].push_back(val[u][i][j]);
int num = min(tmp[0].size(), tmp[1].size());    //能匹配的对数
ans += dep*num;
for(int i = 0; i < num; i++)
{
match[tmp[0][i]] = tmp[1][i];
vis[tmp[0][i]][0] = vis[tmp[1][i]][1] = 1;  //匹配并标记用过
}
return ans;
}

int main(void)
{
int n;
while(cin >> n)
{
init();
memset(vis, 0, sizeof(vis));
for(int i = 1; i <= n; i++)
scanf(" %s", str), Insert(str, 0, i);
for(int i = 1; i <= n; i++)
scanf(" %s", str), Insert(str, 1, i);
printf("%d\n", dfs(0, 0));
for(int i = 1; i <= n; i++)
printf("%d %d\n", i, match[i]);
}
return 0;
}