题目链接:initial bet
initial bet
time limit per test
1 second
memory limit per test
256 megabytes
input
standard input
output
standard output
there are five people playing a game called generosity. each person gives some non-zero number of coins b as an initial bet. after all players make their bets of b coins, the following operation is repeated for several times: a coin is passed from one player to some other player.
your task is to write a program that can, given the number of coins each player has at the end of the game, determine the size b of the initial bet or find out that such outcome of the game cannot be obtained for any positive number of coins b in the initial bet.
input
the input consists of a single line containing five integers c1,?c2,?c3,?c4 and c5 ? the number of coins that the first, second, third, fourth and fifth players respectively have at the end of the game (0?≤?c1,?c2,?c3,?c4,?c5?≤?100).
output
print the only line containing a single positive integer b ? the number of coins in the initial bet of each player. if there is no such value of b, then print the only value -1 (quotes for clarity).
sample test(s)
input
2 5 4 0 4
output
input
4 5 9 2 1
output
-1
note
in the first sample the following sequence of operations is possible:
one coin is passed from the fourth player to the second player; one coin is passed from the fourth player to the fifth player; one coin is passed from the first player to the third player; one coin is passed from the fourth player to the second player.
解题思路:水题,不解释,8分钟交题,虽然一激动少了个条件,忘记判非零了,但是还是在10分钟内出了这题,创了我的cf最快出题纪录了~~~
ac代码:
#include #include #include #include #include #include #include #include #include #include #include #include using namespace std;#define inf 0x7fffffffint main(){ #ifdef sxk freopen(in.txt,r,stdin); #endif int a,b,c,d,e; while(scanf(%d%d%d%d%d,&a,&b,&c,&d,&e)!=eof) { int sum = a + b + c + d + e; if(sum%5 == 0 && sum) printf(%d\n, sum/5); else printf(%d\n, -1); } return 0;}