CodeVS 1710 生日蛋糕 题解

#include <cstdio>using namespace std;int N, M;int ans = ~0u>>1;bool flag;void DFS(int R, int H, int V, int S, int m){if(S>ans)return;if(V>R*R*H*m)return;if(m && !V)return;if(!m && V)return;if(R<m)return;if(H<m)return;if(V<0)return;if(m<0)return;if(V==0 && m==0){if(ans > S)ans = S, flag = true;return;}for(int r = R; r>=m; --r)for(int h = H; h>=m; --h)DFS(r-1, h-1, V-r*r*h, S+2*r*h, m-1);}int main() {scanf("%d %d", &N, &M);for(int R = 70; R>=M; --R)for(int H = (N/R/R); H>=M; --H)DFS(R-1, H-1, N-R*R*H, R*R+2*R*H, M-1);if(flag) printf("%d\n", ans);else printf("0\n");return 0;}