HDU 2602 Find a way BFS搜索
题意:找到总时间最少的KFC
分析:两遍BFS 找KFC比较一下
注:有些地方的KFC可能到达不了,wa了一次
![](https://images.cnblogs.com/OutliningIndicators/ContractedBlock.gif)
#include <iostream> #include <cstdio> #include <algorithm> #include <string> #include <cmath> #include <set> #include <queue> #include <cstring> using namespace std; typedef long long LL; const int maxn=200+5; const int INF=0x3f3f3f3f; char s[maxn][maxn]; int a[maxn][maxn]; int b[maxn][maxn]; int n,m; int dx[4]={0,0,-1,1}; int dy[4]={-1,1,0,0}; struct Point { int x,y; Point(){} Point(int p,int q) { x=p,y=q; } } o,t; queue<Point>Y,M; vector<Point>v; int main() { while(~scanf("%d%d",&n,&m)) { v.clear(); memset(a,-1,sizeof(a)); memset(b,-1,sizeof(b)); for(int i=1;i<=n;++i) scanf("%s",s[i]+1); for(int i=1;i<=n;++i) { for(int j=1;j<=m;++j) { if(s[i][j]=='@')v.push_back(Point(i,j)); else if(s[i][j]=='Y')Y.push(Point(i,j)),a[i][j]=0; else if(s[i][j]=='M')M.push(Point(i,j)),b[i][j]=0; } } while(!Y.empty()) { o=Y.front(); Y.pop(); for(int i=0;i<4;++i) { t.x=o.x+dx[i]; t.y=o.y+dy[i]; if(t.x<1||t.x>n||t.y<1||t.y>m)continue; if(s[t.x][t.y]=='#'||a[t.x][t.y]>=0)continue; a[t.x][t.y]=a[o.x][o.y]+1; Y.push(t); } } while(!M.empty()) { o=M.front(); M.pop(); for(int i=0;i<4;++i) { t.x=o.x+dx[i]; t.y=o.y+dy[i]; if(t.x<1||t.x>n||t.y<1||t.y>m)continue; if(s[t.x][t.y]=='#'||b[t.x][t.y]>=0)continue; b[t.x][t.y]=b[o.x][o.y]+1; M.push(t); } } int ans=INF; for(int i=0;i<v.size();++i) { int x=v[i].x,y=v[i].y; if(a[x][y]==-1||b[x][y]==-1)continue; ans=min(ans,a[x][y]+b[x][y]); } printf("%d\n",ans*11); } return 0; }