01背包 URAL 1073 Square Country

题目传送门

 /*
     题意：问n最少能是几个数的平方和
     01背包：j*j的土地买不买的问题
     详细解释：http://www.cnblogs.com/vongang/archive/2011/10/07/2200721.html
 */
 #include <cstdio>
 #include <algorithm>
 #include <cmath>
 #include <cstring>
 using namespace std;

 const int MAXN = 6e4 + ;
 const int INF = 0x3f3f3f3f;
 int dp[MAXN];

 int main(void)        //URAL 1073 Square Country
 {
     //freopen ("I.in", "r", stdin);

     int n;
     while (scanf ("%d", &n) == )
     {
         memset (dp, , sizeof (dp));
         for (int i=; i<=n; ++i)
         {
             dp[i] = dp[i-] + ;
             for (int j=; j<=sqrt (n*1.0); ++j)
             {
                 if (i >= j * j)    dp[i] = min (dp[i], dp[i-j*j] + );
                 else    break;
             }
         }

         printf ("%d\n", dp[n]);
     }

     return ;
 }