UVa 165 - Stamps

来源：互联网发布：淘宝小号信誉查询编辑：程序博客网时间：2024/04/30 13:26

題目：設計郵票，郵票尺寸相同，每個信封上可以放h張郵票，郵票可以有k種面值，

問能組成的連續面值的最大值。

分析：圖論、搜索。利用回溯法搜索結果，利用dp判斷郵票集合的組合取值；

剪枝优化：每次寻找新值的区间为 [上个值+1，全面取值的最大组合值+1]；

說明：好久沒刷題了╮(╯▽╰)╭。

#include <stdio.h>#include <string.h>int  stamps_ans[10];int  stamps_save[10];int  stamps_used[200];int  stamps_stamp[50];int  stamps_value[10][200];int  max_value = 0;int  stamps_check(int k, int h){int stamps_count = 0;for (int i = 0; i <= k; ++ i)for (int j = 1; j <= h; ++ j)stamps_stamp[stamps_count ++] = stamps_save[i];int V = stamps_save[k]*h;for (int i = 0; i <= h; ++ i)for (int j = 0; j <= V; ++ j)stamps_value[i][j] = 0;for (int i = 0; i <= h; ++ i)stamps_value[i][0] = 1;for (int i = 0; i < stamps_count; ++ i)for (int j = 1; j <= h; ++ j)for (int p = V; p >= stamps_stamp[i]; -- p)if (stamps_value[j-1][p-stamps_stamp[i]])stamps_value[j][p] = 1;int count = 1;while (count <= V && stamps_value[h][count]) count ++;return count-1;}void stamps_dfs(int max, int s, int d, int k, int h){if (k == d) {if (max_value < max-1) {max_value = max-1;for (int i = 0; i < k; ++ i)stamps_ans[i] = stamps_save[i];}return;}for (int i = s; i <= max; ++ i) if (!stamps_used[i]) {stamps_used[i] = 1;stamps_save[d] = i;stamps_dfs(stamps_check(d, h)+1, i+1, d+1, k, h);stamps_used[i] = 0;}}int main(){int h, k;while (~scanf("%d%d",&h,&k) && (k+h)) {max_value = 0;stamps_save[0] = 1;stamps_used[1] = 1;stamps_dfs(h+1, 2, 1, k, h);for (int i = 0; i < k; ++ i)printf("%3d",stamps_ans[i]);printf(" ->%3d\n",max_value);}return 0;}

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