UESTC 2014 Summer Training #3 Div.2

  1 #include <map>
  2 #include <set>
  3 #include <cmath>
  4 #include <ctime>
  5 #include <queue>
  6 #include <stack>
  7 #include <cstdio>
  8 #include <iomanip>
  9 #include <string>
 10 #include <vector>
 11 #include <cstring>
 12 #include <sstream>
 13 #include <iostream>
 14 #include <fstream>
 15 #include <algorithm>
 16 #include <bitset>
 17 #include <climits>
 18 #include <ostream>
 19 #include <ios>
 20 #include <cstdlib>
 21 using namespace std;
 22 
 23 #define wh while
 24 #define inf (int)(~0u/2)
 25 #define FOR(i, n) for(int i = 0; i < n; i++)
 26 #define FOR1(i, n) for(int i = 1; i < n; i++)
 27 #define FOR2(i, n) for(int i = 0; i <= n; i++)
 28 #define REP(i,n) for(int i = 1; i <= n; i++)
 29 #define FORI(it,n) for(typeof(n.begin()) it = n.begin(); it != n.end(); it++)
 30 #define sf scanf
 31 #define pf printf
 32 #define frs first
 33 #define sec second
 34 #define psh push_back
 35 #define mkp make_pair
 36 #define PB(x) push_back(x)
 37 #define MP(x, y) make_pair(x, y)
 38 #define clr(abc,z) memset(abc,z,sizeof(abc))
 39 #define lt(v) v << 1
 40 #define rt(v) v << 1 | 1
 41 #define mid ((l + r) >> 1)
 42 #define lson l, mid, v << 1
 43 #define rson mid + 1, r, v << 1 | 1
 44 
 45 #define fre freopen("1.txt", "r", stdin)
 46 
 47 typedef long long LL;
 48 typedef long double LD;
 49 
 50 const int maxn = 550;
 51 const int bt = 2100;
 52 const int smaxn = 220;
 53 const int INF = 1061109567;
 54 
 55 int dp[smaxn][bt];
 56 bool inq[smaxn][bt];
 57 
 58 struct EDGE{
 59     int v, w;
 60 };
 61 struct NODE{
 62     int id; int state;
 63     NODE(){}
 64     NODE(int x, int y){
 65         id = x; state = y;
 66     }
 67 };
 68 int dx[] = {0, 1, 0, -1};
 69 int dy[] = {1, 0, -1, 0};
 70 
 71 int n, m; int num1, num2;
 72 vector<EDGE> G[maxn];
 73 int stx, sty, edx, edy;
 74 char s[maxn][maxn];
 75 int id[maxn][maxn];
 76 bool vis[maxn][maxn];
 77 
 78 void init(){
 79     clr(id, -1);
 80     num1 = num2 = 0;
 81     FOR(i, smaxn) G[i].clear();
 82     FOR(i, n)
 83         sf("%s", s[i]);
 84     sf("%d%d%d%d", &stx, &sty, &edx, &edy);
 85     stx--; sty--; edx--; edy--;
 86 }
 87 bool isOK(int x, int y){
 88     if(x >= 0 && x < n && y >= 0 && y < m
 89        && s[x][y] != ‘W‘ && s[x][y] != ‘#‘)
 90         return true;
 91     return false;
 92 }
 93 void add(int u, int v, int w){
 94     EDGE tmp; tmp.v = v; tmp.w = w;
 95     G[u].PB(tmp);
 96 }
 97 int getnear(int x, int y, int& t){
 98     clr(vis, 0);
 99     wh(s[x][y] != ‘0‘ && s[x][y] != ‘$‘){
100         t++;
101         if(s[x][y] == ‘L‘) y--;
102         else if(s[x][y] == ‘R‘) y++;
103         else if(s[x][y] == ‘U‘) x--;
104         else if(s[x][y] == ‘D‘) x++;
105         if(!isOK(x, y)) return -1;
106         if(vis[x][y]) return -1;
107         vis[x][y] = true;
108     }
109     return id[x][y];
110 }
111 int getlong1(int x){
112     int ans = 0;
113     wh(x){
114         if(x & 1) ans++;
115         x >>= 1;
116     }
117     return ans;
118 }
119 
120 
121 int main(){
122     wh(sf("%d%d", &n, &m) != EOF){
123         init();
124         FOR(i, n) FOR(j, m)
125             if(s[i][j] == ‘$‘) id[i][j] = num1++;
126         num2 = num1;
127         FOR(i, n) FOR(j, m)
128             if(s[i][j] == ‘0‘) id[i][j] = num2++;
129         FOR(i, n) FOR(j, m)
130             if(id[i][j] != -1){
131                 int u = id[i][j];
132                 FOR(k, 4){
133                     int tx = i + dx[k]; int ty = j + dy[k];
134                     int tm = 1;
135                     if(isOK(tx, ty)){
136                         int v = getnear(tx, ty, tm);
137                         if(v != -1)
138                             add(u, v, tm);
139                     }
140                 }
141             }
142         int idst = id[stx][sty]; int ided = id[edx][edy];
143 
144         queue<NODE> Q;
145         wh(!Q.empty()) Q.pop(); Q.push(NODE(idst, 0));
146         clr(dp, 0x3f); clr(inq, 0);
147         dp[idst][0] = 0; inq[idst][0] = true;
148         wh(!Q.empty()){
149             int u = Q.front().id;
150             int state0 = Q.front().state; Q.pop();
151             inq[u][state0] = false;
152             int ns, nt, nv;
153             FOR(i, (int)G[u].size()){
154                 ns = state0; nt = dp[u][state0];
155                 nv = G[u][i].v; nt += G[u][i].w;
156                 if(nv < num1 && (((1 << nv) & ns) == 0)){
157                     nt += 2; ns |= (1 << nv);
158                 }
159                 if(dp[nv][ns] > nt){
160                     dp[nv][ns] = nt;
161                     if(!inq[nv][ns]){
162                         Q.push(NODE(nv, ns));
163                         inq[nv][ns] = true;
164                     }
165                 }
166             }
167         }
168         int ans = INF, ft = -1;
169         FOR(i, (1 << num1)){
170             int btlong = getlong1(i);
171             if(btlong > ft && dp[ided][i] < INF){
172                 ans = dp[ided][i]; ft = btlong;
173             }
174         }
175         if(ans == INF) pf("-1\n");
176         else pf("%d\n", ans);
177     }
178 }