HDU - 1495 非常可乐（BFS）

题目大意：中文题意

解题思路：裸BFS

#include 
#include 
#include 
using namespace std;
const int N = 110;
const int INF = 0x3f3f3f3f;

int vol[3];
int num[N][N];
int dir[6][3]= {{0, 1, 2}, {0, 2, 1}, {1, 2, 0}, {1, 0, 2}, {2, 1, 0}, {2, 0, 1}};
struct Node{
    int v[3];
    Node() {}
    Node(int v1, int v2, int v3){
        v[0] = v1;
        v[1] = v2;
        v[2] = v3;
    }
};

void bfs() {
    if (vol[0] % 2) {
        printf("NO\n");
        return ;
    }

    memset(num, 0x3f, sizeof(num));
    queue Q;
    Q.push(Node(vol[0], 0, 0));
    num[vol[0]][0] = 0;

    while (!Q.empty()) {
        Node t = Q.front(); Q.pop();
        int v[3];
        for (int i = 0; i < 6; i++) {
            v[dir[i][1]] = (t.v[dir[i][0]] + t.v[dir[i][1]] >= vol[dir[i][1]] ? vol[dir[i][1]] : t.v[dir[i][0]] + t.v[dir[i][1]]);
            v[dir[i][0]] = (t.v[dir[i][0]] + t.v[dir[i][1]] - v[dir[i][1]]);
            v[dir[i][2]] = (t.v[dir[i][2]]);
            if (num[v[0]][v[1]] > num[t.v[0]][t.v[1]] + 1) {
                num[v[0]][v[1]] = num[t.v[0]][t.v[1]] + 1;
                Q.push(Node(v[0], v[1], v[2]));
            }
        }
    }
    int ans = INF;
    if (vol[1] >= vol[0] / 2)
        ans = min(ans, num[vol[0] / 2][vol[0] / 2]);
    if (vol[2] >= vol[0] / 2)
        ans = min(ans, num[vol[0] / 2][0]);
    if (vol[1] >= vol[0] / 2 && vol[2] >= vol[0] / 2)
        ans = min(ans, num[0][vol[0] / 2]);

    if (ans == INF)
        printf("NO\n");
    else 
        printf("%d\n", ans);
}

int main() {
    while (scanf("%d%d%d", &vol[0], &vol[1], &vol[2]) != EOF && vol[0] + vol[1] + vol[2]) bfs();
    return 0;
}