Codeforces 467D - Fedor and Essay (反向建图 + DFS)

题意

给出原文的几个单词和几组替换词，要求最后包含的r最少，长度越短越好。

思路

因为替换的终点肯定可以确定（R最少的单词），所以可以反向建图，把所有单词按照r排序以后DFS一遍，把它们能走到的点的r和size都更新为自己的r、size。

然后直接统计文章中的单词的r和sz

代码

  
  
  
  

   
   
   
   
#include <stack>
   
   
   
   
#include <cstdio>
   
   
   
   
#include <list>
   
   
   
   
#include <set>
   
   
   
   
#include <iostream>
   
   
   
   
#include <string>
   
   
   
   
#include <vector>
   
   
   
   
#include <queue>
   
   
   
   
#include <functional>
   
   
   
   
#include <cstring>
   
   
   
   
#include <algorithm>
   
   
   
   
#include <cctype>
   
   
   
   
#include <string>
   
   
   
   
#include <map>
   
   
   
   
#include <cmath>
   
   
   
   
using namespace std;
   
   
   
   
#define LL long long
   
   
   
   
#define ULL unsigned long long
   
   
   
   
#define SZ(x) (int)x.size()
   
   
   
   
#define Lowbit(x) ((x) & (-x))
   
   
   
   
#define MP(a, b) make_pair(a, b)
   
   
   
   
#define MS(arr, num) memset(arr, num, sizeof(arr))
   
   
   
   
#define PB push_back
   
   
   
   
#define X first
   
   
   
   
#define Y second
   
   
   
   
#define ROP freopen("input.txt", "r", stdin);
   
   
   
   
#define MID(a, b) (a + ((b - a) >> 1))
   
   
   
   
#define LC rt << 1, l, mid
   
   
   
   
#define RC rt << 1|1, mid + 1, r
   
   
   
   
#define LRT rt << 1
   
   
   
   
#define RRT rt << 1|1
   
   
   
   
#define BitCount(x) __builtin_popcount(x)
   
   
   
   
#define BitCountll(x) __builtin_popcountll(x)
   
   
   
   
#define LeftPos(x) 32 - __builtin_clz(x) - 1
   
   
   
   
#define LeftPosll(x) 64 - __builtin_clzll(x) - 1
   
   
   
   
const double PI = acos(-1.0);
   
   
   
   
const int INF = 0x3f3f3f3f;
   
   
   
   
const double eps = 1e-8;
   
   
   
   
const int MAXN = 2e5 + 10;
   
   
   
   
const int MOD = 29;
   
   
   
   
const int dir[][2] = { {1, 0}, {0, 1} };
   
   
   
   
int cases = 0;
   
   
   
   
typedef pair<int, int> pii;
   
   
   
   

   
   
   
   
struct NODE
   
   
   
   
{
   
   
   
   
 int id, rNum, sz;
   
   
   
   
 bool operator < (const NODE &a) const
   
   
   
   
 {
   
   
   
   
 if (rNum != a.rNum) return rNum < a.rNum;
   
   
   
   
 return sz < a.sz;
   
   
   
   
 }
   
   
   
   
};
   
   
   
   

   
   
   
   
void ChangeToLower(string &str)
   
   
   
   
{
   
   
   
   
 for (int i = 0; i < SZ(str); i++) str[i] = tolower(str[i]);
   
   
   
   
}
   
   
   
   

   
   
   
   
int CountR(const string &str)
   
   
   
   
{
   
   
   
   
 int cnt = 0;
   
   
   
   
 for (int i = 0; i < SZ(str); i++)
   
   
   
   
 if (str[i] == 'r') cnt++;
   
   
   
   
 return cnt;
   
   
   
   
}
   
   
   
   

   
   
   
   
map<string, int> oddId;
   
   
   
   
map<int, int> newId;
   
   
   
   
int cnt;
   
   
   
   
vector<NODE> words;
   
   
   
   

   
   
   
   
int GetNumber(string &tmp)
   
   
   
   
{
   
   
   
   
 ChangeToLower(tmp);
   
   
   
   
 if (oddId.count(tmp)) return oddId[tmp];
   
   
   
   
 oddId[tmp] = cnt;
   
   
   
   
 int r = CountR(tmp);
   
   
   
   
 words.PB((NODE){cnt, r, SZ(tmp)});
   
   
   
   
 cnt++;
   
   
   
   
 return cnt - 1;
   
   
   
   
}
   
   
   
   

   
   
   
   
vector<int> G[MAXN], article;
   
   
   
   
int vis[MAXN];
   
   
   
   

   
   
   
   
void DFS(int curId, int r, int sz)
   
   
   
   
{
   
   
   
   
 vis[curId] = 1;
   
   
   
   
 for (int i = 0; i < SZ(G[curId]); i++)
   
   
   
   
 {
   
   
   
   
 int tmpId = G[curId][i];
   
   
   
   
 if (!vis[tmpId])
   
   
   
   
 {
   
   
   
   
 vis[tmpId] = 1;
   
   
   
   
 words[newId[tmpId]].rNum = r;
   
   
   
   
 words[newId[tmpId]].sz = sz;
   
   
   
   
 DFS(tmpId, r, sz);
   
   
   
   
 }
   
   
   
   
 }
   
   
   
   
}
   
   
   
   

   
   
   
   
int main()
   
   
   
   
{
   
   
   
   
 //ROP;
   
   
   
   
 int n;
   
   
   
   
 cin >> n;
   
   
   
   
 for (int i = 0; i < n; i++)
   
   
   
   
 {
   
   
   
   
 string tmp;
   
   
   
   
 cin >> tmp;
   
   
   
   
 int curNumber = GetNumber(tmp);
   
   
   
   
 article.PB(curNumber);
   
   
   
   
 }
   
   
   
   
 int ncnv;
   
   
   
   
 cin >> ncnv;
   
   
   
   
 for (int i = 0; i < ncnv; i++)
   
   
   
   
 {
   
   
   
   
 string tmp;
   
   
   
   
 cin >> tmp;
   
   
   
   
 int u = GetNumber(tmp);
   
   
   
   
 cin >> tmp;
   
   
   
   
 int v = GetNumber(tmp);
   
   
   
   
 G[v].PB(u);
   
   
   
   
 }
   
   
   
   
 sort(words.begin(), words.end());
   
   
   
   
 for (int i = 0; i < SZ(words); i++) newId[words[i].id] = i;
   
   
   
   
 for (int i = 0; i < SZ(words); i++)
   
   
   
   
 if (!vis[words[i].id]) DFS(words[i].id, words[i].rNum, words[i].sz);
   
   
   
   
 LL rAns = 0, szAns = 0;
   
   
   
   
 for (int i = 0; i < SZ(article); i++)
   
   
   
   
 rAns += words[newId[article[i]]].rNum, szAns += words[newId[article[i]]].sz;
   
   
   
   
 cout << rAns << " " << szAns << endl;
   
   
   
   
 return 0;
   
   
   
   
}