CF 1042B. Vitamins(状压dp)

Posted 2021-02-15 komorabi

以此题开始进入学习状压dp~

题目大意

输入每瓶维生素的价格以及所含维生素元素，若能买到包含abc三种维生素，输出所需最小价钱，否则输出-1.

题解

状压dp，每种维生素对应一位，求出数值7(即二进制111)所对应的价格

代码

 1 #include <iostream>
 2 #include <string>
 3 #include <algorithm>
 4 using namespace std;
 5 
 6 int main()
 7 {
 8     int dp[8], tmp[8], n, c;
 9     string s;
10     cin >> n;
11     for (int i = 0; i <= 7; i++) dp[i] = 0x3f3f3f3f, tmp[i] = 0;
12     for (int i = 0; i < n; i++) {
13         cin >> c >> s;
14         for (int j = 0; j < s.size(); j++) {
15             if (s[j] == ‘A‘) tmp[i] |= 1;
16             if (s[j] == ‘B‘) tmp[i] |= 2;
17             if (s[j] == ‘C‘) tmp[i] |= 4;
18         }
19         dp[tmp[i]] = min(dp[tmp[i]], c);
20     }
21     for (int i = 0; i <= 7; i++)
22         for (int j = 0; j <= 7; j++)
23             dp[i | j] = min(dp[i | j], dp[i] + dp[j]);
24     if (dp[7] < 0x3f3f3f3f) cout << dp[7] << endl;
25     else cout << -1 << endl;
26 
27 }