贪心 Codeforces Round #173 (Div. 2) B. Painting Eggs

题目传送门

 /*
     题意：给出一种方案使得abs (A - G) <= 500，否则输出-1
     贪心：每次选取使他们相差最小的，然而并没有-1:)
 */
 #include <cstdio>
 #include <cstring>
 #include <iostream>
 #include <cmath>
 #include <algorithm>
 using namespace std;

 const int MAXN = 1e6 + ;
 const int INF = 0x3f3f3f3f;

 int main(void)        //Codeforces Round #173 (Div. 2) B. Painting Eggs
 {
 //    freopen ("B.in", "r", stdin);

     int n;
     while (scanf ("%d", &n) == )
     {
         string ans = "";    int sum_a = , sum_g = ;
         for (int i=; i<=n; ++i)
         {
             int x, y;
             scanf ("%d%d", &x, &y);
             if (abs (sum_a + x - sum_g) <= abs (sum_g + y - sum_a))    {ans += "A";    sum_a += x;}
             else    {ans += 'G';    sum_g += y;}
         }

         cout << ans << endl;
     }

     return ;
 }