【模拟8.07】走格子
这题一定是个模拟题......
怎么可能.......考场被完美骗到
其实这题是最短路问题啦啦啦啦..........
对于每个墙与墙，我们因为联通的门的存在，所以我们直接将与它相邻的格子连在一起喽
当然暴搜也能骗到85分......
不说了，就当复习一边堆优化dijkstar了....
1 #include<cstdio> 2 #include<iostream> 3 #include<cmath> 4 #include<algorithm> 5 #include<cstring> 6 #include<string> 7 #include<map> 8 #include<vector> 9 #include<queue> 10 #include<set> 11 #define MAXN 1010 12 #define ps push_back 13 #define int long long 14 using namespace std; 15 struct node{int to,n,w;}e[250001*42];int head[350001],tot1; 16 void add(int u,int v,int w) 17 { 18 e[++tot1].to=v;e[tot1].n=head[u];e[tot1].w=w;head[u]=tot1; 19 } 20 int a[MAXN][MAXN];int n,m; 21 queue<int>q; 22 set<int>hang[MAXN],lie[MAXN]; 23 void find_pre(int th,int &x,int &y) 24 { 25 if(th%m==0) 26 { 27 y=m; 28 x=th/m; 29 return ; 30 } 31 y=th%m; 32 x=th/m+1; 33 } 34 int find_sur(int l,int r) 35 { 36 return (l-1)*m+r; 37 } 38 bool bian[MAXN*MAXN]; 39 void g_kx(int one,int l,int r,int x) 40 { 41 if(l>n||l<1)return ; 42 if(r>m||r<1)return ; 43 if(a[l][r]==0) 44 { 45 add(x,one,1); 46 add(one,x,1); 47 if(bian[one]==0) 48 { 49 q.push(one); 50 bian[one]=1; 51 } 52 //printf("1--l=%lld r=%lld x_l=%lld x_r=%lld\n",l,r,l,r); 53 } 54 return ; 55 } 56 void BFS(int top) 57 { 58 q.push(top);bian[top]=1; 59 while(!q.empty()) 60 { 61 int x=q.front();q.pop(); 62 int l;int r; 63 find_pre(x,l,r); 64 //printf("%lld %lld\n",l,r); 65 int one=find_sur(l-1,r),two=find_sur(l,r-1); 66 int three=find_sur(l+1,r),four=find_sur(l,r+1); 67 //printf("one=%lld two=%lld\n",one,two); 68 g_kx(one,l-1,r,x);g_kx(two,l,r-1,x); 69 g_kx(three,l+1,r,x);g_kx(four,l,r+1,x); 70 } 71 } 72 int one1,two1,three1,four1; 73 int minn; 74 void the_walk_sur(int i,int j,int x) 75 { 76 set<int>::iterator it,it2; 77 it=it2=hang[i].upper_bound(x); 78 it2--; 79 one1=*it;two1=*it2; 80 two1++;one1--;//one 右 two 左 81 int l,r; 82 find_pre(one1,l,r);minn=min(minn,r-j+1); 83 find_pre(two1,l,r);minn=min(minn,j-r+1); 84 // printf("one1=%lld two1=%lld\n",one1,two1); 85 it=it2=lie[j].upper_bound(x); 86 it2--; 87 three1=*it;four1=*it2;four1+=m;three1-=m; 88 find_pre(three1,l,r);minn=min(minn,l-i+1); 89 find_pre(four1,l,r);minn=min(minn,i-l+1); 90 //three 上 four 下 91 } 92 int fir_x,fir_y,end_x,end_y; 93 char c[MAXN][MAXN]; 94 int dis[MAXN*MAXN]; 95 priority_queue<pair<int,int> >qq; 96 void connect(int x,int to,int w) 97 { 98 if(dis[to]>dis[x]+w) 99 { 100 dis[to]=dis[x]+w; 101 bian[to]=1; 102 qq.push(make_pair(-dis[to],to)); 103 int l,r;find_pre(to,l,r); 104 //printf("connect x=%lld to=%lld l=%lld r=%lld\n",x,to,l,r); 105 } 106 } 107 void diss(int x) 108 { 109 dis[x]=0; 110 qq.push(make_pair(dis[x],x)); 111 while(!qq.empty()) 112 { 113 int id=qq.top().second;int mm=qq.top().first; 114 int l,r;find_pre(id,l,r); 115 //printf("----id=%lld l=%lld r=%lld %lld\n",id,l,r,-mm); 116 bian[id]=0; 117 qq.pop(); 118 minn=1000000000; 119 the_walk_sur(l,r,id); 120 if(minn<1000000000) 121 { 122 connect(id,one1,minn); 123 connect(id,two1,minn); 124 connect(id,three1,minn); 125 connect(id,four1,minn); 126 } 127 for(int i=head[id];i;i=e[i].n) 128 { 129 int to=e[i].to; 130 find_pre(to,l,r); 131 //printf("dis[%lld]=%lld %lld %lld\n",to,dis[to],l,r); 132 if(dis[id]+e[i].w<dis[to]) 133 { 134 dis[to]=dis[id]+e[i].w; 135 bian[to]=1; 136 find_pre(to,l,r); 137 //printf("dis[%lld]=%lld %lld %lld\n",to,dis[to],l,r); 138 qq.push(make_pair(-dis[to],to)); 139 } 140 } 141 } 142 } 143 signed main() 144 { 145 scanf("%lld%lld",&n,&m); 146 memset(dis,0x3f3f3f,sizeof(dis)); 147 for(int i=1;i<=n;++i) 148 { 149 for(int j=1;j<=m;++j) 150 { 151 cin>>c[i][j]; 152 if(c[i][j]=='#') 153 { 154 a[i][j]=1; 155 hang[i].insert(find_sur(i,j)); 156 lie[j].insert(find_sur(i,j)); 157 } 158 if(c[i][j]=='C') 159 { 160 fir_x=i;fir_y=j; 161 } 162 if(c[i][j]=='F') 163 { 164 end_x=i;end_y=j; 165 } 166 } 167 } 168 BFS(find_sur(fir_x,fir_y)); 169 memset(bian,0,sizeof(bian)); 170 diss(find_sur(fir_x,fir_y)); 171 int anss=dis[find_sur(end_x,end_y)]; 172 if(anss==4557430888798830399) 173 printf("no\n"); 174 else 175 printf("%lld\n",anss); 176 } 177 /* 178 15 15 179 ############### 180 #......#....#.# 181 #.......#.....# 182 ##.....#.#...## 183 #..##.........# 184 #.#...##....#.# 185 #........#..#.# 186 #...........#.# 187 #...##...##.F.# 188 #....#.##..##.# 189 ##..C........##//11 190 ###........##.# 191 ###...........# 192 #..##.........# 193 ############### 194 */
