[pat]1068 Find More Coins
2018-09-05 21:18 legend聪 阅读(189) 评论(0) 编辑 收藏 举报满背包问题,把体积和价值看成相等的。用滚动数组优化,然后额外开辟一个choice数组来记录每次的选择,然后回溯打印。因为要按字典序,先把价值进行排序。假如选最小的商品能装满m的话,那就把判断条件改成大于等于,然后最后来
#include<bits/stdc++.h> using namespace std; int dp[105]; int w[10005]; bool flag[10005]; bool choice[10005][105]; int n, m; bool cmp(int a, int b) { return a > b; } int main() { memset(flag, false, sizeof(flag)); fill(choice[0], choice[0] +105, false); fill(dp, dp +105, 0); scanf("%d %d", &n, &m); int i, j; for (i = 1; i <= n; i++) { scanf("%d", &w[i]); } sort(w+1, w + n+1,cmp); for (i = 1; i <= n; i++) { for (j = m; j >= w[i]; j--) { if (dp[j-w[i]]+w[i]>=dp[j]) { dp[j] = dp[j - w[i]] + w[i]; choice[i][j] = true; } } } int x=n, y=m; int num = 0; if (dp[m] != m) { printf("No Solution\n"); } else { while (x >= 1) { if (choice[x][y] == true) { flag[x] = true;//下标 num++; y -= w[x]; } x--; } for (i = n; i >= 1; i--) { if (flag[i] == true) { if (num - 1 > 0) { printf("%d ", w[i]); num--; } else printf("%d\n", w[i]); } } } }
选择最小的那个。