标签：
题意：迷宫搜索，一个起点可能有多个终点，遇到门卫要额外花费一个单位时间；
思路：bfs;
结构体表示队列：
#include<cstdio> #include<cstring> #include<algorithm> using namespace std; int n,m,s1,s2,e1,e2; char mm[505][505]; int vis[505][505]; int shortest[505][505]; int dir[4][2]={{1,0},{-1,0},{0,1},{0,-1}}; struct node { int x,y; node(){} node(int x,int y) { this->x=x; this->y=y; } }q[500010]; int bfs() { int b=0,e=0; q[e++]=node(s1,s2); vis[s1][s2]=1; shortest[s1][s2]=1; while(b<e) { node now=q[b++]; for(int i=0;i<4;i++) { int xx=now.x+dir[i][0]; int yy=now.y+dir[i][1]; if(xx<0||xx>=n||yy<0||yy>=m||vis[xx][yy]||mm[xx][yy]==‘#‘) continue; if(mm[xx][yy]==‘r‘) { return shortest[now.x][now.y]; } vis[xx][yy]=1; shortest[xx][yy]=shortest[now.x][now.y]+1; if(mm[xx][yy]==‘x‘) { shortest[xx][yy]++; } q[e++]=node(xx,yy); } } return -1; } int main() { int i,j,k,ans; while(scanf("%d%d",&n,&m)!=EOF) { memset(mm,0,sizeof(mm)); memset(vis,0,sizeof(vis)); memset(shortest,0,sizeof(shortest)); for(i=0;i<n;i++) { for(j=0;j<m;j++) { scanf(" %c",&mm[i][j]); if(mm[i][j]==‘a‘) { s1=i;s2=j; } } } ans=bfs(); if(ans==-1) printf("Poor ANGEL has to stay in the prison all his life.\n"); else printf("%d\n",ans); } }
stl普通队列：
#include<cstdio> #include<cstring> #include<algorithm> #include<queue> using namespace std; int n,m,s1,s2,e1,e2; char mm[505][505]; int vis[505][505]; int shortest[505][505]; int dir[4][2]={{1,0},{-1,0},{0,1},{0,-1}}; struct node { int x,y; }; queue<node> q; int bfs() { int b=0,e=0; while(!q.empty()) q.pop(); node s; s.x=s1,s.y=s2; q.push(s); vis[s1][s2]=1; shortest[s1][s2]=1; while(!q.empty()) { node now=q.front(); q.pop(); for(int i=0;i<4;i++) { int xx=now.x+dir[i][0]; int yy=now.y+dir[i][1]; if(xx<0||xx>=n||yy<0||yy>=m||vis[xx][yy]||mm[xx][yy]==‘#‘) continue; if(mm[xx][yy]==‘r‘) { return shortest[now.x][now.y]; } vis[xx][yy]=1; shortest[xx][yy]=shortest[now.x][now.y]+1; if(mm[xx][yy]==‘x‘) { shortest[xx][yy]++; } node d; d.x=xx;d.y=yy; q.push(d); } } return -1; } int main() { int i,j,k,ans; while(scanf("%d%d",&n,&m)!=EOF) { memset(mm,0,sizeof(mm)); memset(vis,0,sizeof(vis)); memset(shortest,0,sizeof(shortest)); for(i=0;i<n;i++) { for(j=0;j<m;j++) { scanf(" %c",&mm[i][j]); if(mm[i][j]==‘a‘) { s1=i;s2=j; } } } ans=bfs(); if(ans==-1) printf("Poor ANGEL has to stay in the prison all his life.\n"); else printf("%d\n",ans); } }
优先队列：
#include<cstdio> #include<cstring> #include<queue> #include<algorithm> using namespace std; int n,m,s1,s2; char mm[505][505]; int vis[505][505]; int dir[4][2]={{1,0},{-1,0},{0,1},{0,-1}}; struct node { int x,y,t; bool operator<(const node&xx)const { return t>xx.t; } }; int bfs() { priority_queue<node>q; vis[s1][s2]=1; node cur,now; node s; s.x=s1;s.y=s2;s.t=0; q.push(s); while(!q.empty()) { cur=q.top(); q.pop(); for(int i=0;i<4;i++) { now.x=cur.x+dir[i][0]; now.y=cur.y+dir[i][1]; now.t=cur.t+1; if(now.x<0||now.x>=n||now.y<0||now.y>=m||vis[now.x][now.y]||mm[now.x][now.y]==‘#‘) continue; if(mm[now.x][now.y]==‘r‘) return now.t; if(mm[now.x][now.y]==‘x‘) { now.t++; } vis[now.x][now.y]=1; q.push(now); } } return -1; } int main() { int i,j,k,ans; while(scanf("%d%d",&n,&m)!=EOF) { memset(mm,0,sizeof(mm)); memset(vis,0,sizeof(vis)); for(i=0;i<n;i++) { for(j=0;j<m;j++) { scanf(" %c",&mm[i][j]); if(mm[i][j]==‘a‘) { s1=i;s2=j; } } } ans=bfs(); if(ans==-1) printf("Poor ANGEL has to stay in the prison all his life.\n"); else printf("%d\n",ans); } }
标签：
原文地址：http://www.cnblogs.com/dashuzhilin/p/4470636.html
