Uva 1587：Box

Posted 2023-03-04 xietx1995

题目传送门：https://cn.vjudge.net/problem/UVA-1587

#include <stdio.h>

struct p

    int w, h;
ps[6], cps[3];

bool isSame(int i, int j)

    return (ps[i].w == ps[j].w && ps[i].h == ps[j].h)
        || (ps[i].w == ps[j].h && ps[i].h == ps[j].w);


bool dfs(int a, int b, int depth) // 旋转拼接三个板子

    if (2 == depth) 
        if (a == cps[depth].w && b == cps[depth].h) return true;
        if (a == cps[depth].h && b == cps[depth].w) return true;
        return false;
    
    if (cps[depth].w == a)
        if (dfs(cps[depth].h, b, depth+1))
            return true;
    if (cps[depth].h == a)
        if (dfs(cps[depth].w, b, depth+1))
            return true;
    return false;


int main()

    while (2 == scanf("%d%d", &ps[0].w, &ps[0].h)) 
        bool used[6] = false; int ct = 0;
        for (int i = 1; i < 6; ++i)
            scanf("%d%d", &ps[i].w, &ps[i].h);

        for (int i = 0, j; i < 6; ++i)  // 首先确定是否有三对相同的板子
            if (used[i]) continue;
            for (j = i + 1; j < 6; ++j) 
                if (used[j]) continue;
                if (isSame(i, j)) 
                    used[i] = used[j] = true;
                    cps[ct++] = ps[i]; // 记住三组板子
                    break;
                
            
            if (6 == j)
                break;
        
        //printf("ct = %d\\n", ct);
        if (ct < 3)  printf("IMPOSSIBLE\\n"); continue; 

        if (dfs(cps[0].w, cps[0].h, 1) || dfs(cps[0].h, cps[0].w, 1)) // 旋转拼接三个板子
            printf("POSSIBLE\\n");
        else
            printf("IMPOSSIBLE\\n");
    
    return 0;