POJ 3087 Shuffle ' m Up (DFS)

Title Link: Shuffle ' m up

Test instructions: There are two character sequences with a and b length n, and now define the operation:

The characters A, B are merged into a sequence C, and the top N of c is classified as a, and the bottom n is a B

Given a, b and a target sequence C, ask at least how many operations a, C to convert

Parse: Put a, b into the hash table, and then simulate the operation process directly DFS can.

AC Code:

#include <cstdio> #include <iostream> #include <cstring> #include <map>using namespace Std;int n , ans, cnt;string c;map<string, int> sti;bool vis[5010][5010], tg;void dfs (string A, string b, int dep) {if (!sti.    Count (a)) sti[a] = cnt++;    Use map instead of hash table if (!sti.count (b)) sti[b] = cnt++;    if (Vis[sti[a]][sti[b]]) return;    VIS[STI[A]][STI[B]] = true;    string S;        for (int i=0; i<n; i++) {//Cross S.push_back (B[i]);    S.push_back (A[i]);        } if (s = = c) {if (dep < ans) ans = dep;        TG = true;    return;    } a.clear ();    B.clear ();    for (int i=0; i<n; i++) A.push_back (S[i]);    The top n is classified as a for (int i=n; i<2*n; i++) B.push_back (S[i]); The following n are classified as Dfs B (A, b, dep+1);}    int main () {//Freopen ("In.txt", "R", stdin);    int t;    scanf ("%d", &t);        for (int kase=1; kase<=t; kase++) {string A, B;        CNT = 0;        ans = 0x7ffffff;        cin>>n>>a>>b>>c; Memset (vis, false, sizeof (VIS));        TG = false;        Sti.clear ();        DFS (A, B, 1);        printf ("%d", Kase);        if (TG) printf ("%d\n", ans);    Else puts ("-1"); } return 0;}

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POJ 3087 Shuffle ' m Up (DFS)