hdu1195 Open the Lock

一道bfs的题目,不敢说水..好吧,这题的确是入门题....

因为自己做了快2小时..

还是因为思维考虑的不全面的缘故;

一开始把加减的情况都写在了一个循环里...交了一遍,WA..

检查了挺久才检查出来的....把过程打印出来也有不靠谱的地方...

后来分析了一下逻辑...发现之前的修改会影响到后面对数字的修改;其实就是我做了2次修改,才记录了一次;

而且这种做法还会使压入队列的情况减少...

后来修改的时候吧加法改少了一部分...又花了一点时间debug..

不过怎么说..最后还是做出来了...

#include <iostream>
#include <queue>
#include <string.h>
#include <algorithm>
using namespace std;
#define maxn 10005
struct node{
    int count;
    int a[4];
};
bool visit[maxn];
int N;
int begin_value,end_value;
int getValue(int *a)
{
    int result = 0;
    for (int i = 0; i < 4; i++){
        result = result * 10 + a[i];
    }
    return result;
}
int bfs()
{
    queue<node> game;
    node cur, next;
    cur.count = 0;
    cur.a[0] = begin_value / 1000;
    cur.a[1] = (begin_value % 1000) / 100;
    cur.a[2] = (begin_value % 100) / 10;
    cur.a[3] = begin_value % 10;
    game.push(cur);
    visit[getValue(cur.a)] = true;
    while (!game.empty()){
        cur = game.front();
        game.pop();
        int value = getValue(cur.a);
        //printf("%d %d
", value,cur.count);
        if (value == end_value){
            return cur.count;
        }
        //减法:
        for (int i = 0; i < 4; i++){
            next = cur;
            if (cur.a[i] == 1){
                next.a[i] = 9;
                if (!visit[getValue(next.a)])
                {
                    next.count = cur.count + 1;
                    visit[getValue(next.a)] = true;
                    game.push(next);
                }
            }
            else{
                next.a[i] = cur.a[i] - 1;
                if (!visit[getValue(next.a)])
                {
                    next.count = cur.count + 1;
                    visit[getValue(next.a)] = true;
                    game.push(next);
                }

            }
        }
        //加法
        for (int i = 0; i < 4; i++){
            next = cur;
            if (cur.a[i] == 9){
                next.a[i] = 1;
                if (!visit[getValue(next.a)])
                {
                    next.count = cur.count + 1;
                    visit[getValue(next.a)] = true;
                    game.push(next);
                }
            }
            else{
                next.a[i] = cur.a[i] + 1;
                if (!visit[getValue(next.a)])
                {
                    next.count = cur.count + 1;
                    visit[getValue(next.a)] = true;
                    game.push(next);
                }
            }
        }
        for (int i = 0; i < 3; i++)
        {
            next = cur;
            swap(next.a[i], next.a[i + 1]);        
            if (!visit[getValue(next.a)])
            {
                next.count = cur.count + 1;
                visit[getValue(next.a)] = true;
                game.push(next);
                
            }
        }
    }
    return 0;
}

int main()
{
    while (~scanf("%d", &N)){
        while (N--){
            scanf("%d %d", &begin_value, &end_value);
            memset(visit, false, sizeof(visit));
            printf("%d
", bfs());
        }
    }
    return 0;
}