Uvalive 6665 Dragon ' s Cruller (BFS + priority queue +hash)

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Test instructions

A nine Gongge, given your initial state and end state, each lateral move and vertical movement have a certain cost,

Ask for the minimum cost from the initial state to the end state.

Analysis:

BFS, with priority queue maintenance to reach the current state of the optimal value, with a hash to determine whether the current state has been reached.

The code is as follows:

#include <iostream> #include <cstring> #include <cstdio> #include <algorithm> #include < queue>using namespace Std;const int INF = 1e9+7777;int fac[9]= {1,1,2,6,24,120,720,5040,40320};    Cantor unfolded, used to hashstruct nod {int mp[9],pos,cost;    BOOL operator < (const struct NOD &tmp) const {return this->cost > tmp.cost; }} p;int dx[4]= {1,-1,0,0};int dy[4]= {0,0,-1,1};int s[9],e[9];int cv,ch;int vis[40320*9+100];int getHashVal (int *a) {//h    Ash gets the hash value.    int val = 0;        for (int i=0; i<9; i++) {int cnt=0;        for (int j=0; j<i; j + +) cnt+= (A[j]>a[i]);    Val+=cnt*fac[i]; } return Val;    BOOL Check (NOD tmp) {int cnt = 0;    for (int i=0; i<9; i++) cnt+= (Tmp.mp[i]==e[i]); return cnt==9;}    int BFS (nod st) {priority_queue<nod> Q;    Q.push (ST);    Vis[gethashval (ST.MP)]=0; while (!        Q.empty ()) {nod top = Q.top ();        Q.pop ();        if (check (top)) {return top.cost;       } for (int i=0; i<4; i++) {int tmppos = Top.pos;            int nowx = (top.pos/3+dx[i]+3)%3;//convert int nowy = top.pos%3+dy[i];                if (nowy==3) {nowy=0;            nowx= (nowx+1)%3;                } if (nowy==-1) {nowy=2;            nowx= (nowx-1+3)%3;            } swap (Top.mp[nowx*3+nowy],top.mp[tmppos]);            if (i<2) TOP.COST+=CV;            else top.cost+=ch;            Top.pos=nowx*3+nowy;            int val = gethashval (TOP.MP);                if (Top.cost<vis[val]) {Q.push (top);            Vis[val]=top.cost;            } swap (Top.mp[nowx*3+nowy],top.mp[tmppos]);            if (i<2) TOP.COST-=CV;            else top.cost-=ch;        Top.pos=tmppos;    }}}nod init () {NOD St;    for (int i=0; i<40320*9+100; i++) Vis[i]=inf;        for (int i=0; i<9; i++) {st.mp[i]=s[i];    if (s[i]==0) st.pos=i;    } st.cost=0; Return St;} int main() {while (~scanf ("%d%d", &AMP;CH,&AMP;CV)) {if (cv==0&&ch==0) break;        for (int i=0; i<9; i++) scanf ("%d", s+i);        for (int i=0; i<9; i++) scanf ("%d", e+i);    printf ("%d\n", BFS (init ())); } return 0;}  /*4 96 3 08 1 24 5 76 3 08 1 24 5 731 314 3 60 1 58 2 70 3 64 1 58 2 792 41 5 34 0 78 2 61 5 04 7 38 2 612 283 4 50 2 67 1 85 7 18 6 20 3 403196312*/

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Uvalive 6665 Dragon ' s Cruller (BFS + priority queue +hash)