Hangzhou Electric Oj_hdu2616_kill The monster

Main topic:

There was a mountain near Yifenfei's hometown, and a big monster lived in the mountains. As a hero in his hometown, Yifenfei decided to kill the monster.

Now we know Yifenfei has n spells, the Monster's blood volume is M, when the Monster's blood volume <= 0 means the monster was killed. Use different spells at different times, and there is a difference in the effect. Now, with the expression (A, M), tell you the effect of each of these spells. A means that the magic can knock out the monster a point of blood. M means that when the monster's blood volume is <= m, magic damage is doubled.

Input:

The input contains many test data. The first two integers per test n,m (2 < n < ten, 1 < m < 10^7), n represents the number of spells Yifenfei, and M represents the amount of monster blood. The next n lines, each line represents a magic (AI,MI). (0 < Ai, Mi <=m).

Output:

Each use case outputs an integer that represents the minimum number of spells that Yifenfei kills monsters. If Yifenfei can't kill monster output-1.

1#include <stdio.h>2#include <stdlib.h>3#include <string.h>4 5 //data structure for recording spell damage situation6typedefstructNode7 {8     intA;9     intM;Ten }node; One  ANode spells[Ten]; - BOOLvisit[Ten];//tag Array to determine if a spell has been used - intSpellcount;//Feifei Number of spells possessed the intMincount;//The minimum number of spells needed to kill a monster -  - /*Data Initialization Functions*/ - voidInit () + { -Mincount =Ten; +memset (Visit,0,sizeof(visit)); A } at  - /*DFS Search*/ - voidDfsintCountintHP) - { -     if(Spellcount = = Count && HP >0)//all spells are exhausted, monster hp > 0, return False -         return; in     Else if(Mincount <= count && HP >0)//currently using more spells than Mincount, Monster hp > 0, description Continue search no value, return false -         return; to     Else if(Mincount > Count && HP <=0)//the number of spells currently used is smaller than mincount, and the monster HP <=0 indicates a better way to find than before. Returns True +     { -Mincount =count; the         return; *     } $ Panax Notoginseng      for(inti =0; i < Spellcount; ++i) -     { the         if(false==Visit[i]) +         { AVisit[i] =true; the             intharm = (HP <= spells[i]. M?2*Spells[i]. A:spells[i]. A); +DFS (Count +1, HP-harm); -Visit[i] =false; $         } $     } - } -  the intMainvoid) - {Wuyi     intGpt//Moster ' s HP the      while(SCANF ("%d%d", &spellcount, &hp)! =EOF) -     { Wu init (); -          for(inti =0; i < Spellcount; ++i) Aboutscanf"%d%d", &spells[i]. A, &Spells[i]. M); $Dfs0, HP); -         if(Ten!=mincount) -printf"%d\n", mincount); -         Else Aprintf"-1\n"); +     } the     return 0; -}

Hangzhou Electric Oj_hdu2616_kill The monster