actoder abc 344 51 D - String Bags(分组背包)

actoder abc 344 51 D - String Bags(分组背包)

前情提要

本来太菜了，上来就用的爆搜，剪枝，也是直接T了9个样例

思路

k组字符串，每组可以选一个或者不选，典型的分组背包问题

代码

#include<iostream>
#include<cstring>
#include<vector>
using namespace std;

const int N = 110;
int f[N][N];

int main() {
	string t;
	cin >> t;
	int len = t.size();
	int n;
	cin >> n;
	memset(f, 0x3f, sizeof f);
	f[0][0] = 0;
	for (int i = 1; i <= n; i++) {
		int k;
		cin >> k;
		vector<string> s(k);
		for (int j = 0; j < k; j++) cin >> s[j];
		for (int j = 0; j <= len; j++) f[i][j] = f[i - 1][j];//不选择字符串
		for (int j = 0; j < k; j++) {
			int tmp = len - s[j].size();
			for (int l = 0; l <= tmp; l++)
				if (f[i - 1][l] < 1e9 && t.substr(l, s[j].size()) == s[j])
					f[i][l + s[j].size()] = min(f[i][l + s[j].size()], f[i - 1][l] + 1);//选择字符串
		}
	}
	if (f[n][len] > 1e9) cout << -1 << endl;
	else cout << f[n][len] << endl;
	return 0;
}