hdoj 1010 Repair the Wall(贪心)

分手后的思念是犯贱 2022-04-03 15:56 184阅读 0赞

# Repair the Wall #

##### Time Limit : 5000/1000ms (Java/Other) Memory Limit : 32768/32768K (Java/Other) #####

##### Total Submission(s) : 13 Accepted Submission(s) : 7 #####

Problem Description

Long time ago , Kitty lived in a small village. The air was fresh and the scenery was very beautiful. The only thing that troubled her is the typhoon.  
  
When the typhoon came, everything is terrible. It kept blowing and raining for a long time. And what made the situation worse was that all of Kitty's walls were made of wood.  
  
One day, Kitty found that there was a crack in the wall. The shape of the crack is  
a rectangle with the size of 1×L (in inch). Luckly Kitty got N blocks and a saw(锯子) from her neighbors.  
The shape of the blocks were rectangle too, and the width of all blocks were 1 inch. So, with the help of saw, Kitty could cut down some of the blocks(of course she could use it directly without cutting) and put them in the crack, and the wall may be repaired perfectly, without any gap.  
  
Now, Kitty knew the size of each blocks, and wanted to use as fewer as possible of the blocks to repair the wall, could you help her ?

Input

The problem contains many test cases, please process to the end of file( EOF ).  
Each test case contains two lines.  
In the first line, there are two integers L(0<L<1000000000) and N(0<=N<600) which  
mentioned above.  
In the second line, there are N positive integers. The i th integer Ai(0<Ai<1000000000 ) means that the i th block has the size of 1×Ai (in inch).

Output

For each test case , print an integer which represents the minimal number of blocks are needed.  
If Kitty could not repair the wall, just print "impossible" instead.

Sample Input

5 3
    3 2 1
    5 2
    2 1
      
       
      
       
    
      
       
      
       
        
       //解题思路：此题求解最少使用的木块数，可切割，先从大到小排序，贪心思想：每次都取最大的。
      
       
      
       
       
        #include<stdio.h>
    #include<stdlib.h>
    #include<algorithm>
    int cmp(const void* a,const void* b)  //从大到小
    {
        return *(int *)b - *(int *)a;
    }
    int main()
    {
        int L,N,i,j,count,k;
        int ss[700];
        while(scanf("%d%d",&L,&N)!=EOF)
        {
            for(i=0;i<N;i++)
            {
                scanf("%d",&ss[i]);
            }
            qsort(ss,N,sizeof(ss[0]),cmp);
      //      for(i=0;i<N;i++)
        //    printf("%d ",ss[i]);
            count=0;k=0;j=0;
                for(i=0;i<N;i++)
                {
                    if(ss[i]+k < L)
                    {
                        k+=ss[i];
                        count++;
                    }
                    else
                    {
                        count++;
                        j=1;
                        printf("%d\n",count);
                        break;
                    }
                }
                if(j==0)
            printf("impossible\n");
        }
        return 0;
    }