uva10626 Buying Coke（DP）

题目链接：http://uva.onlinejudge.org/index.php?option=com_onlinejudge&Itemid=8&category=11&page=show_problem&problem=1567

此题状态即为各种硬币个数，然后分类讨论即可。

#include <stdio.h>
#include <string.h>
#include <algorithm>
using namespace std;
int t;
int num, n[3], dp[705][220][100], vis[705][220][100];

int dfs(int num, int n1, int n2, int n3) {
    int &sum = dp[n1][n2][n3];
    int &flag = vis[n1][n2][n3];
    if (flag) 
    return sum;
    else if (num == 0) {
    flag = 1;
    sum = 0;
    return sum;
    }
    else {
    sum = 2000000000;
    if (n1 >= 8) sum = min(sum, dfs(num - 1, n1 - 8, n2, n3) + 8);
    if (n2 >= 1 && n1 >= 3) sum = min(sum, dfs(num - 1, n1 - 3, n2 - 1, n3) + 4);
    if (n3 >= 1 && n1 >= 3) sum = min(sum, dfs(num - 1, n1 - 3, n2 + 1, n3 - 1) + 4);
    if (n2 >= 2) sum = min(sum, dfs(num - 1, n1 + 2, n2 - 2, n3) + 2);
    if (n3 >= 1) sum = min(sum, dfs(num - 1, n1 + 2, n2, n3 - 1) + 1);
    flag = 1;
    return sum;
    }
}

int main() {
    scanf("%d", &t);
    while (t --) {
    memset(vis, 0, sizeof(vis));
    scanf("%d", &num);
    for (int i = 0; i < 3; i ++)
        scanf("%d", &n[i]);
    printf("%d
", dfs(num, n[0], n[1], n[2]));
    }
    return 0;
}