BZOJ4004 [JLOI2015]装备购买

首先按照价格从小到大排序，然后一个个查看能不能加进去。。。

裸的拟阵我去QAQ

不过理解起来的话，可以这样子想，就是类似高斯消元的步骤。。。只不过消元是有顺序的

 

 1 /**************************************************************
 2     Problem: 4004
 3     User: rausen
 4     Language: C++
 5     Result: Accepted
 6     Time:812 ms
 7     Memory:2840 kb
 8 ****************************************************************/
 9  
10 #include <cstdio>
11 #include <cmath>
12 #include <algorithm>
13  
14 using namespace std;
15 typedef double lf;
16 const int N = 505;
17  
18 inline int read() {
19     static int x;
20     static char ch;
21     x = 0, ch = getchar();
22     while (ch < '0' || '9' < ch)
23         ch = getchar();
24     while ('0' <= ch && ch <= '9') {
25         x = x * 10 + ch - '0';
26         ch = getchar();
27     }
28     return x;
29 }
30  
31 template <class T> int sgn(T x) {
32     static T eps = 1e-5;
33     if (fabs(x) < eps) return 0;
34     return eps > 0 ? 1 : -1;
35 }
36  
37 struct data {
38     int c;
39     lf v[N];
40      
41     inline lf& operator [] (int i) {
42         return v[i];
43     }
44      
45     inline void get(int m) {
46         static int i;
47         for (i = 1; i <= m; ++i) v[i] = read();
48     }
49      
50     inline bool operator < (const data &p) const {
51         return c < p.c;
52     }
53 } a[N];
54  
55 int n, m;
56 int w[N], ans1, ans2;
57  
58 int main() {
59     int i, j, k;
60     lf tmp;
61     n = read(), m = read();
62     for (i = 1; i <= n; ++i) a[i].get(m);
63     for (i = 1; i <= n; ++i) a[i].c = read();
64     sort(a + 1, a + n + 1);
65      
66     for (i = 1; i <= n; ++i)
67         for (j = 1; j <= m; ++j) if (sgn(a[i][j]) == 1) {
68             if (w[j]) {
69                 tmp = a[i][j] / a[w[j]][j];
70                 for (k = j; k <= m; ++k) a[i][k] -= tmp * a[w[j]][k];
71             } else {
72                 w[j] = i;
73                 ++ans1, ans2 += a[i].c  ;
74                 break;
75             }
76         }
77     printf("%d %d\n", ans1, ans2);
78     return 0;
79 }
View Code

 

posted on 2015-04-22 21:42  Xs酱~  阅读(391)  评论(0)  编辑  收藏  举报