题意
$5\times 7$ 版本的折纸小鸟对对碰,并且规定了只有 $n$ 次操作( $n\le 5$ )。
题解
注意到数据范围极小,不难想到暴力,但是直接暴力递归算出来微超。
所以考虑剪枝,最重要的剪枝就是判断无解,简单来说,当一种存在的颜色小于等于两种时,很显然不能再消去了,无解。
代码
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 | #include<bits/stdc++.h>using namespace std;
 
 typedef long long ll;
 
 typedef pair<int , int > pii;
 typedef unsigned long long ull;
 
 namespace FastIO
 {
 
 
 template<typename T> inline T read(T& x) {
 x = 0;
 int f = 1;
 char ch;
 while (!isdigit(ch = getchar())) if (ch == '-') f = -1;
 while (isdigit(ch)) x = (x << 1) + (x << 3) + (ch ^ 48), ch = getchar();
 x *= f;
 return x;
 }
 template<typename T, typename... Args> inline void read(T& x, Args &...x_) {
 read(x);
 read(x_...);
 return;
 }
 inline ll read() {
 ll x;
 read(x);
 return x;
 }
 };
 using namespace FastIO;
 
 const int dx[2] = {1, -1};
 
 int n;
 int a[10][10][10];
 
 inline void Input() {
 read(n); int x;
 for(int i = 1; i <= 5; i++) {
 for(int j = 1; j <= 8; j++) {
 read(x);
 if(x == 0) break;
 a[0][i][j] = x;
 }
 }
 }
 
 struct Node {
 int x, y, g;
 Node(int x = 0, int y = 0, int g = 0)
 : x(x), y(y), g(g) {}
 };
 vector<Node >opt;
 
 inline bool Empty(int tmp);
 inline void Copy(int tmp);
 inline void Down(int tmp);
 inline bool Clear(int tmp);
 inline bool Check(int tmp);
 
 inline void Dfs(int cnt) {
 
 
 
 
 
 
 
 
 if(cnt == n + 1) {
 if(Empty(cnt - 1)) {
 for(auto &p : opt) {
 printf("%d %d %d\n", p.x, p.y, p.g);
 }
 return exit(0);
 }
 return ;
 }
 for(int r = 1; r <= 5; r++) {
 for(int c = 1; c <= 7; c++) {
 if(a[cnt-1][r][c] == 0) continue;
 for(int k = 0; k < 2; k++) {
 Copy(cnt);
 
 
 
 
 
 
 
 
 int nr = r + dx[k];
 
 if(nr < 1 || nr > 5 || a[cnt][r][c] == a[cnt][nr][c]) continue;
 if(k == 1 && a[cnt][r][c] && a[cnt][nr][c]) continue;
 swap(a[cnt][r][c], a[cnt][nr][c]);
 do {
 Down(cnt);
 }while(Clear(cnt));
 if(Check(cnt)) continue;
 opt.push_back(Node(r-1, c-1, dx[k]));
 Dfs(cnt + 1);
 opt.pop_back();
 }
 }
 }
 }
 
 inline void Work() {
 Dfs(1);
 printf("-1\n");
 }
 
 int main() {
 int T = 1;
 while(T--) {
 Input();
 Work();
 }
 return 0;
 }
 
 inline bool Empty(int tmp) {
 for(int i = 1; i <= 5; i++) {
 for(int j = 1; j <= 7; j++) {
 if(a[tmp][i][j] != 0) return false;
 }
 }
 return true;
 }
 inline void Copy(int tmp) {
 for(int i = 1; i <= 5; i++) {
 for(int j = 1; j <= 7; j++) {
 a[tmp][i][j] = a[tmp-1][i][j];
 }
 }
 }
 inline void Down(int tmp) {
 for(int i = 1; i <= 5; i++) {
 int p[10], cnt = 0;
 for(int j = 1; j <= 7; j++) {
 if(a[tmp][i][j]) {
 p[++cnt] = a[tmp][i][j];
 }
 a[tmp][i][j] = 0;
 }
 for(int j = 1; j <= cnt; j++) {
 a[tmp][i][j] = p[j];
 }
 }
 }
 int vis[10][10];
 inline void Checkx(int tmp, int i, int j) {
 if(a[tmp][i][j] == 0) return ;
 if(a[tmp][i+1][j] != a[tmp][i][j]) return ;
 if(a[tmp][i+2][j] != a[tmp][i][j]) return ;
 vis[i][j] = vis[i+1][j] = vis[i+2][j] = 1;
 }
 inline void Checky(int tmp, int i, int j) {
 if(a[tmp][i][j] == 0) return ;
 if(a[tmp][i][j+1] != a[tmp][i][j]) return ;
 if(a[tmp][i][j+2] != a[tmp][i][j]) return ;
 vis[i][j] = vis[i][j+1] = vis[i][j+2] = 1;
 }
 inline bool Clear(int tmp) {
 bool flag = 0;
 for(int i = 1; i <= 5; i++) {
 for(int j = 1; j <= 7; j++) {
 vis[i][j] = 0;
 }
 }
 for(int i = 1; i <= 5; i++) {
 for(int j = 1; j <= 5; j++) {
 Checky(tmp, i, j);
 }
 }
 for(int j = 1; j <= 7; j++) {
 for(int i = 1; i <= 3; i++) {
 Checkx(tmp, i, j);
 }
 }
 for(int i = 1; i <= 5; i++) {
 for(int j = 1; j <= 7; j++) {
 if(vis[i][j]) {
 a[tmp][i][j] = 0, flag = 1;
 }
 }
 }
 return flag;
 }
 inline bool Check(int tmp) {
 int p[15];
 for(int i = 1; i <= 10; i++) p[i] = 0;
 for(int i = 1; i <= 5; i++) {
 for(int j = 1; j <= 7; j++) {
 p[a[tmp][i][j]]++;
 }
 }
 for(int i = 1; i <= 10; i++) {
 if(p[i] != 0 && p[i] < 3) return true;
 }
 return false;
 }
 
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