DFS-生日蛋糕

生日蛋糕

一道深搜题，看了这两个博客才懂的。

http://blog.csdn.net/blesslzh0108/article/details/53486168

http://blog.csdn.net/v5zsq/article/details/46575215

#include<iostream>
#include<algorithm>
#include<cstdio>
using namespace std;
const int maxn = 0x3f3f3f3f;
int minv[], mins[];
int ans, mh,n, m;

void dfs(int v, int s, int level, int r, int h)
{
    if (level == ) {
        if (v == n&&s < ans)
            ans = s;
        return;
    }
    if (v + minv[level - ] > n) return;
    if (s + mins[level - ] > ans) return;
    if ( * (n - v) / r + s >= ans) return;
    for (int i = r - ; i >= level; i--) {
        if (level == m) s = i*i;
        mh = min(h - , (n - v - minv[level - ]) / (i*i));
        for (int j = mh; j >= level; j--)
            dfs(v + i*i*j, s +  * i*j, level - , i, j);
    }
}

int main()
{
    minv[] = , mins[] = ;
    for (int i = ; i <= ; i++) {
        minv[i] = minv[i - ] + i*i*i;
        mins[i] = mins[i - ] +  * i*i;
    }
    while (scanf("%d%d",&n,&m)==)
    {
        ans = maxn;
        dfs(, , m, n + , n + );
        if (ans == maxn)  ans = ;
        printf("%d\n", ans);
    }
    return ;
}