BZOJ 1293: [SCOI2009]生日礼物 贪心

 1 #include <iostream>
 2 #include <cstdio>
 3 #include <cstring>
 4 #include <algorithm>
 5 #define inf 0x7f7f7f7f;
 6 using namespace std;
 7 int n,m;
 8 int i,j;
 9 int l,hh;
10 long long ans,maxn,minn;
11 long long now[61],places[61];
12 int counts[61],num[61];
13 int a[61][100001];
14 int main()
15 {    
16     scanf("%d%d",&n,&m);
17     for (i=1;i<=m;i++) {
18       scanf("%d",&num[i]);
19         for (j=1;j<=num[i];j++) {
20           scanf("%d",&a[i][j]);
21           if (j==1) {
22           now[i]=a[i][j];//记录位置
23           places[i]=j;//记录下标
24         }
25         }
26     }
27     ans=inf;
28     while (hh!=n-m+1) {
29         maxn=-inf; minn=inf; l=0;hh++; 
30         for (i=1;i<=m;i++) {
31           if (now[i]>maxn) maxn=now[i];
32           if (now[i]<minn) {
33             minn=now[i]; l=i;
34     }
35         if (now[i]==minn) {
36          if (a[i][places[i]+1]<=a[l][places[l]+1]){
37            minn=now[i];
38            l=i;
39             }
40         }
41     }
42     //printf("%d %d\n",maxn,minn);
43           if (places[l]!=num[l]) {
44             now[l]=a[l][places[l]+1];
45             places[l]++;
46             //pos=places[i];
47         }//贪心移动区间
48         if (maxn-minn<ans) ans=maxn-minn; //更新答案
49     
50     }
51     printf("%lld",ans);
52 }
53