HDU-1069 Monkey and Banana 动态规划
简单动态规划,将长方体分解成六个,然后二重排序后,DP即可。
对于当前方块,选择前面的能够放置的方块的最大值加上本身的高度。
代码如下:
#include <cstdlib> #include <cstring> #include <cstdio> #include <algorithm> #define MAXN 200 using namespace std; // 对于每个长方体,有三种不同的方法。 int N, dp[MAXN]; struct Node { int x, y, z; }e[MAXN]; inline int max(int x, int y) { return x > y ? x : y; } bool cmp(const Node &a, const Node &b) { if (a.x != b.x) return a.x > b.x; else return a.y > b.y; } int judge(int a, int b) { if (e[a].x > e[b].x && e[a].y > e[b].y) { return 1; } else { return 0; } } int DP() { int Max = 0; memset(dp, 0, sizeof (dp)); for (int i = 1; i <= 6*N; ++i) { dp[i] = e[i].z; Max = max(Max, dp[i]); // 没加这一句,一直WA for (int j = 1; j < i; ++j) { if (judge(j, i)) { dp[i] = max(dp[i], dp[j]+e[i].z); Max = max(Max, dp[i]); } } } return Max; } int main() { int ca = 1; while (scanf("%d", &N), N) { for (int i = 1; i <= 6*N; i+=6) { scanf("%d %d %d", &e[i].x, &e[i].y, &e[i].z); e[i+1].x = e[i].y, e[i+1].y = e[i].z, e[i+1].z = e[i].x; e[i+2].x = e[i].z, e[i+2].y = e[i].y, e[i+2].z = e[i].x; e[i+3].x = e[i].x, e[i+3].y = e[i].z, e[i+3].z = e[i].y; e[i+4].x = e[i].z, e[i+4].y = e[i].x, e[i+4].z = e[i].y; e[i+5].x = e[i].y, e[i+5].y = e[i].x, e[i+5].z = e[i].z; } sort(e+1, e+1+6*N, cmp); printf("Case %d: maximum height = %d\n", ca++, DP()); } return 0; }