Cod sursă (job #378091)

#include<bits/stdc++.h>
#define x first
#define y second
using namespace std;

struct lol {
	int x, y, x2,y2;
} s[30];

pair<int,int> a[30];
int n,m,q,N;
int M[30][30];
int dx[] = {0,-1,0,1};
int dy[] = {-1,0,1,0};
bool u;

ofstream fout("immortal.out");
	
bool OK(int i, int j) {
	return (i>=1 && j>=1 && j<=m && i<=n);
}
int rs;
void BT(int k) {
	if (k==N) {
		for (int i=1; i<k; i++) {
			fout<<s[i].x<<" "<<s[i].y<<" "<<s[i].x2<<" "<<s[i].y2<<'\n';
		}
		exit(0);
	}
	for (int i=1; i<=N; i++) {
		int posi=a[i].x, posj=a[i].y;
		if (!M[posi][posj]) continue; 
		for (int d=0; d<4; d++) {
			int i2=posi + dx[d];
			int j2=posj + dy[d];
			int i3 = i2 + dx[d];
			int j3 = j2 + dy[d];
			if (OK(i3, j3) && M[i2][j2] && !M[i3][j3]) {
				M[i2][j2] = M[posi][posj] = 0;
				a[i].x = i3;
				a[i].y = j3;
				M[i3][j3] = 1;
				s[k]= {posi, posj, i3, j3};
				BT(k+1);
				
				M[i2][j2] = M[posi][posj] = 1;
				M[i3][j3] = 0;
				a[i].x = posi;
				a[i].y = posj;
			}
		}
	}
	
}


int main() { 
	ifstream cin("immortal.in");
	cin>>n>>m>>q;
	
	while (q--) {
		++N;
		cin>>a[N].x>>a[N].y;
		M[a[N].x][a[N].y] = 1;
	}
	BT(1);
	
	
	return 0;
}