P2033 Chessboard Dance
今天集训第四天，遇到这道模拟题。
我搞错了一大问题。首先我以为移动是整行移动，但显然不是的。于是我就开始想这个怎么处理：
我想是先碰到之后让箱子作为P，继续往后推，再碰到箱子……最后回溯。这是可怕的递归，函数是 MOVE(x, y, Steps_rem)。奈何码力不足，写了一下午。
回家之后就会了 😅，其实递归是可以的，但其实只需要走一步，不需要搞一个Step变量，纯粹是问题复杂化。
但是呢，也有一些东西要注意：平面坐标系和数组意义的坐标系是不一样的，把人烦死。
#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define IOS ios::sync_with_stdio(false); cin.tie(0); cout.tie(0);
#define CHECK cout<<"WALKED"<<endl;
inline int read(){int x=0,f=1;char ch=getchar();while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();} while(ch>='0' && ch<='9')x=(x<<3)+(x<<1)+ch-'0',ch=getchar();return x*f;}
ll qpow(ll a, ll b, ll mod){ll res = 1; while (b > 0){if (b & 1) res = res * a % mod;a = a * a % mod; b >>= 1; } return res;}
using namespace std;char mp[100][100];
string opt, optf;
struct Person {int x, y;int dx, dy;
}P;bool check(int tx, int ty)
{if (tx >= 1 && tx <= 8 && ty >= 1 &&ty <= 8) return true;return false;
}void MOVE(int nowx, int nowy)
{int nx = nowx + P.dx;int ny = nowy + P.dy;if (!check(nx, ny))return;if (mp[nx][ny] != '.') {MOVE(nx, ny);}mp[nx][ny] = mp[nowx][nowy];mp[nowx][nowy] = '.';P.x = nx;P.y = ny;
}int main()
{for (int i = 1; i <= 8; i++)for (int j = 1; j <= 8; j++) {cin >> mp[i][j];if (mp[i][j] == '^') P = {i, j, -1, 0};else if (mp[i][j] == '<') P = {i, j, 0, -1};else if (mp[i][j] == 'v') P = {i, j, 1, 0};else if (mp[i][j] == '>') P = {i, j, 0, 1};}int n;while (true){opt = "", optf = "";cin >> opt;if (opt == "#") break;if (opt == "turn") cin >> optf;if (opt == "move") cin >> n;if (opt == "move") {for (int i = 1; i <= n; i++) {MOVE(P.x, P.y);}}if (optf == "left") {if (P.dx == -1 && P.dy == 0) P.dx = 0, P.dy = -1;else if (P.dx == 0 && P.dy == -1) P.dx = 1, P.dy = 0;else if (P.dx == 1 && P.dy == 0) P.dx = 0, P.dy = 1;else if (P.dx == 0 && P.dy == 1) P.dx = -1, P.dy = 0;}else if (optf == "right") {if (P.dx == -1 && P.dy == 0) P.dx = 0, P.dy = 1;else if (P.dx == 0 && P.dy == 1) P.dx = 1, P.dy = 0;else if (P.dx == 1 && P.dy == 0) P.dx = 0, P.dy = -1;else if (P.dx == 0 && P.dy == -1) P.dx = -1, P.dy = 0;}else if (optf == "back") {if (P.dx == 1 && P.dy == 0) P.dx = -1, P.dy = 0;else if (P.dx == 0 && P.dy == 1) P.dx = 0, P.dy = -1;else if (P.dx == -1 && P.dy == 0) P.dx = 1, P.dy = 0;else if (P.dx == 0 && P.dy == -1) P.dx = 0, P.dy = 1;}}for (int i = 1; i <= 8; i++) {for (int j = 1; j <= 8; j++) {if (i == P.x && j == P.y) {if (P.dx == 1 && P.dy == 0) cout << 'v';else if (P.dx == 0 && P.dy == 1) cout << '>';else if (P.dx == -1 && P.dy == 0) cout << '^';else if (P.dx == 0 && P.dy == -1) cout << '<';continue;}cout << mp[i][j];}cout<<endl;}return 0;
}
