问题 C: 【宽搜入门】8数码难题

#include <iostream>
#include <cstdio>
#include <cstring>
#include <algorithm>
#include <stack>
#include <climits>
#include <vector>
#include <cmath>
#include <queue>

using namespace std;
struct node {
    int matrix[3][3];
    int step, x, y;
    int last[2];
};
int ans;

int d_x[4] = {-1, 0, 1, 0};
int d_y[4] = {0, 1, 0, -1};

bool judge(int x, int y) {
    return !(x < 0 || x > 2 || y < 0 || y > 2);
}

bool cmp(const node &n1, const node &n2) {
    for (int i = 0; i < 3; ++i) {
        for (int j = 0; j < 3; ++j) {
            if (n1.matrix[i][j] != n2.matrix[i][j]) return false;
        }
    }
    return true;
}


node start, dest;

void solve() {

    queue<node> q;
    q.push(start);
    int step = start.step;
    while (!q.empty()) {
        auto t = q.front();
        q.pop();

        if (cmp(t, dest)) {
            printf("%d\n", t.step);
            return;
        }

        int x = t.x;
        int y = t.y;
        if (step != t.step) {
            step = t.step;
        }

        for (int i = 0; i < 4; ++i) {
            int new_x = x + d_x[i];
            int new_y = y + d_y[i];
            if (judge(new_x, new_y) && (new_x!= t.last[0] || new_y!=t.last[1])) {

                int matrix[3][3];
                memcpy(matrix, t.matrix, sizeof(t.matrix));
                swap(matrix[t.x][t.y], matrix[new_x][new_y]);
                node temp;
                temp.x =new_x;
                temp.y =new_y;
                temp.step = step+1;
                temp.last[0] = t.x;
                temp.last[1] = t.y;
                memcpy(temp.matrix, matrix, sizeof(matrix));
                q.push(temp);

            }
        }

    }


}

int main() {
    
    ans = 0;

  

    for (int i = 0; i < 3; ++i) {
        for (int j = 0; j < 3; ++j) {
            scanf("%d", &start.matrix[i][j]);

            if (start.matrix[i][j] == 0) {
                start.x = i;
                start.y = j;
            }
        }
    }
    start.step = 1;


 
    for (int i = 0; i < 3; ++i) {
        for (int j = 0; j < 3; ++j) {
            scanf("%d", &dest.matrix[i][j]);
        }
    }
  


    solve();




    return 0;
}