codefores741B Arpa's weak amphitheater and Mehrdad's valuable Hoses(并查集+背包)

题意：

给出一些女孩的体重和美貌程度，这些女孩是按照组在一起的，要么选一整个组，要么只能选组里的一个，最后求总重量为W的女孩最大美貌程度

要求：

这一看就是并查集+背包，主要是这个选择的问题，用背包时按组数遍历，每次状态转移一整个组或遍历整个组转移其中一个女孩，这里面的状态转移一开始没怎么搞清楚。

#include<iostream>#include<string>#include<algorithm>#include<functional>#include<cstring>#include<vector>using namespace std;const int N = 1005;int n, m, weight;int fa[N], w[N],b[N];int dp[N];vector<int> group[N];int find(int x){return fa[x] == x ?x: fa[x] = find(fa[x]);}int main(){cin >> n >> m >> weight;for (int i = 1; i <= n; i++)scanf("%d", &w[i]);for (int i = 1; i <= n; i++)scanf("%d", &b[i]);for (int i = 1; i <= n; i++) fa[i] = i;for (int i = 1; i <= m; i++){int u, v;cin >> u >> v;int x = find(u);int y = find(v);if (x != y){fa[x] = y;}}for (int i = 1; i <= n; i++){int x = find(i);group[x].push_back(i);}memset(dp, 0, sizeof(dp));for (int i = 1; i <= n; i++){int x = find(i);if (i != x)continue;for (int j = weight; j >= 0; j--){int sumb = 0, sumw = 0;for (int k = 0; k < group[x].size(); k++){sumb += b[group[x][k]];sumw += w[group[x][k]];if (j >= w[group[x][k]])dp[j] = max(dp[j], dp[j - w[group[x][k]]]+ b[group[x][k]]);}if (j >= sumw)dp[j] = max(dp[j], dp[j - sumw]+sumb);}}printf("%d\n", dp[weight]);return 0;}