Submission #8575

#	TimeUTC-0	Username	Problem	Language	Result	Execution time	Memory
8575	2014-09-17 10:27:09	angel	지우개 (GA4_eraser)	C++98	6 / 100	24 ms	2260 KiB

eraser

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
#include <stdio.h>
#include <algorithm>
#define mod 1000000007
#define inv 166666668
int n;
int a[100005];
long long s[100005];
int f(long long a, long long b, long long c)
{
  a %= mod, b %= mod, c %= mod;
  return (((a * b) % mod) * c) % mod;
}
int main()
{
  long long ans = 0, sum = 0;
  scanf("%d", &n);
  for(int i=0; i<n; i++) {
    scanf("%d", &a[i]);
    sum = (sum + a[i]) % mod;
    s[a[i]]++;
  }
  std::sort(a, a + n);
  ans = f(sum, sum, sum);
  for(int i=1; i<=100000; i++) {
    ans = (ans - (f(s[i], s[i], s[i]) * f(i, i, i)) % mod) % mod;
    ans = (ans + mod) % mod;
    ans = (ans - 3 * f(f(s[i], s[i], sum - i * s[i]), i, i)) % mod;
    ans = (ans + mod) % mod;
  }
  printf("%lld\n", (ans * inv) % mod);
 
 
הההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההההה
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX

• Subtask 1: 6 / 6
• Subtask 2: 0 / 7
• Subtask 3: 0 / 16
• Subtask 4: 0 / 17
• Subtask 5: 0 / 26
• Subtask 6: 0 / 28