Codeforces Round #273 (Div. 2)
A题
1 s = sum(map(int, raw_input().split())) 2 print s / 5 if s % 5 == 0 and s / 5 else -1
Ｂ题
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
Ｃ题
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
Ｄ题
1 /************************************************************************* 2 > File Name: D.cpp 3 > Author: Stomach_ache 4 > Mail: [email protected] 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 }