POJ 3278 Catch that Cow

Problem-Solving ideas: Simple wide search, the key is pruning.

1#include <cstdio>2#include <cstring>3#include <algorithm>4#include <queue>5 using namespacestd;6 Const intMAXN =100005;7 intVIS[MAXN];//Mark whether this point has passed8 intN, K;9 Ten  One structnode{ A     intx, CNT; - }p, now; -  theQueue<node>Q; -  - intBFsintXintCNT) - { +memset (Vis,0,sizeof(VIS));//initialized to never go through -      while(!q.empty ()) Q.pop (); +p.x = x, p.cnt =CNT; A Q.push (p); at  -      while(!q.empty ()) -     { -p =Q.front (); - Q.pop (); -  in         if(p.x = = k)returnp.cnt;//go to that point and return directly to the number of steps -  tonow.x = p.x +1, now.cnt = p.cnt +1; +         if(Now.x <=100000&&!vis[now.x])//critical pruning, not traversed and within the data range that meets the topic -         { theVis[now.x] =1;//marked as having traversed * Q.push (now); $         }Panax Notoginseng  -now.x = p.x-1, now.cnt = p.cnt +1; the         if(Now.x >=0&&!vis[now.x]) +         { AVis[now.x] =1; the Q.push (now); +         } -  $now.x =2* p.x, now.cnt = p.cnt +1; $         if(Now.x <=100000&&!vis[now.x]) -         { -Vis[now.x] =1; the Q.push (now); -         }Wuyi     } the     return-1;//won't come to this step - } Wu  - intMain () About { $      while(~SCANF ("%d%d", &n, &k)) -     { -         intAns = BFS (n,0); -printf"%d\n", ans); A     } +     return 0; the}

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POJ 3278 Catch that Cow