7-39 魔法优惠券 (25分)--sort()

//sort(a+i,a+j)------->a[i]到a[j-1]被排序。
 1 #include <iostream>
 2 #include <algorithm>
 3 
 4 using namespace std;
 5 long int pos[1000001], neg[1000001],price[1000001];
 6 long int N, M;
 7 long int k1 = -1, k2 = -1;
 8 long int p1 = -1, p2 = -1;
 9 bool cmp_less(long int a,long int b)
10 {
11     return a > b;
12 }
13 bool cmp_greater(long int a, long int b)
14 {
15     return a < b;
16 }
17 int main()
18 {
19     cin >> N;
20     for (long int i = 0; i < N; i++)
21     {
22         long int temp; cin >> temp;
23         if (temp > 0)
24         {
25             pos[++k1] = temp;
26         }
27         else
28         {
29             neg[++k2] = temp;
30         }
31     }
32     cin >> M;
33     for (long int i = 0; i < M; i++)
34     {
35         cin >> price[i];
36     }
37     sort(pos, pos + N,cmp_less);
38     sort(neg, neg + N, cmp_greater);
39     sort(price, price + M, cmp_less);
40     long int sum = 0;
41     long int p = M - 1;
42     long int flag = 0;
43 
44     for (long int i = 0; i < M; i++)
45     {
46         if (price[i] < 0 && flag == 0)
47         {    
48             sort(price + i, price + M, cmp_greater);
49             flag = 1;
50         }
51         if (price[i] > 0)
52         {
53             if (k1 != p1)
54             {
55                 sum += price[i] * pos[++p1];
56             }
57         }
58         if (price[i] < 0)
59         {
60             if (k2 != p2)
61             {
62                 sum += price[i] * neg[++p2];
63             }
64         }
65     }
66     cout << sum;
67     return 0;
68 }