Codeforces Round #273 (Div. 2)

1 s = sum(map(int, raw_input().split()))
2 print s / 5 if s % 5 == 0 and s / 5 else -1

1 n, m = map(int, raw_input().split())
2 div, lft = n / m, n % m;
3 mi = (div + 1) * (div) / 2 * lft + (div) * (div - 1) / 2 * (m - lft);
4 print mi, (n - m + 1) * (n - m) / 2

1 a = map(int, raw_input().split())
2 a.sort()
3 print a[0] + a[1] if (a[0] + a[1]) * 2 <= a[2] else sum(a) / 3

 1 /*************************************************************************
 2     > File Name: D.cpp
 3     > Author: Stomach_ache
 4     > Mail: sudaweitong@gmail.com
 5     > Created Time: 2014年10月17日 星期五 21时39分21秒
 6     > Propose: 
 7  ************************************************************************/
 8 #include <cmath>
 9 #include <string>
10 #include <cstdio>
11 #include <fstream>
12 #include <cstring>
13 #include <iostream>
14 #include <algorithm>
15 using namespace std;
16 /*Let‘s fight!!!*/
17 
18 const int MOD = 1e9 + 7;
19 const int MAX_N = 200050;
20 int dp[MAX_N];
21 
22 int main(void) {
23       ios_base::sync_with_stdio(false);
24     int r, g;
25     cin >> r >> g;
26     int h = 1;
27     while (h * (h + 1) / 2 <= r + g) h++;
28     h--;
29 
30     memset(dp, 0, sizeof(dp));
31     dp[0] = 1;
32     for (int i = 1; i <= h; i++) {
33           for (int j = r; j >= i; j--) {
34               dp[j] = (dp[j] + dp[j - i]) % MOD;
35         }
36     }
37     h = h * (h + 1) / 2;
38     int res = 0;
39     for (int i = 0; i <= r; i++) if (i + g >= h) res = (res + dp[i]) % MOD;
40     cout << res << endl;
41 
42     return 0;
43 }