Cod sursă (job #295616)

#include <bits/stdc++.h>
using namespace std;
ifstream f("immortal.in");
ofstream g("immortal.out");
const int nMax = 25;
struct Pct{
    int xs, ys, xf, yf;
};
Pct sol[nMax];
pair <int, int > a[nMax];
int dx[] = {-1,0,1,0};
int dy[] = {0,1,0,-1};
int dx2[] = {-2,0,2,0};
int dy2[] = {0,2,0,-2};
int n ,m;
bool there[nMax][nMax], done;
inline bool Ok(int x, int y) {
    if(x > n || x < 1 || y < 1 || y > m) {
        return 0;
    }
    return 1;
}
inline void Back(int top, int nemuritori) {
    if(top == nemuritori) {
        done = 1;
        for(int i = 1; i < top; i++) {
            g<< sol[i].xs << " " << sol[i].ys << " " << sol[i].xf << " " << sol[i].yf << "\n";
        }
    }
    for(int i = 1; i <= nemuritori; i++) {
        if(done) {
            return;
        }
        int x = a[i].first;
        int y = a[i].second;
        if(there[x][y]) {
            for(int k = 0; k < 4; k++) {
                int nx = x + dx[k];
                int ny = y + dy[k];
                int nxvec = x + dx2[k];
                int nyvec = y + dy2[k];
                if(Ok(nxvec,nyvec) && there[nx][ny] && !there[nxvec][nyvec]){
                    there[x][y] = 0;
                    there[nx][ny] = 0;
                    there[nxvec][nyvec] = 1;
                    a[i].first = nxvec;
                    a[i].second = nyvec;
                    sol[top].xs = x;
                    sol[top].ys = y;
                    sol[top].xf = nxvec;
                    sol[top].yf = nyvec;
                    Back(top + 1, nemuritori);
                    a[i].first = x;
                    a[i].second = y;
                    there[x][y] = 1;
                    there[nx][ny] = 1;
                    there[nxvec][nyvec] = 0;
                }
            }
        }
    }
    return;
}
int main()
{
    int k;
    f >> n >> m >> k;
    for(int i = 1; i <= k; i++) {
        f>> a[i].first >> a[i].second;
        there[a[i].first][a[i].second] = 1;
    }
    Back(1,k);
    return 0;
}