第三题： int main() {     int n;     cin >> n;     vector<vector<int>> a(4, vector<int>(4));     for (int i = 0; i < 4; i++)         for (int j = 0; j < 4; j++)             cin >> a[i][j];     if (n == 1) {         for (int j = 0; j < 4; j++) {             int ll = 0;             for (int i = 0; i < 4; i++) {                 if (a[i][j] == 0)                     continue;                 if (i + 1 < 4 && a[i][j] == a[i + 1][j]) {                     a[i][j] *= 2;                     a[i + 1][j] = 0;                 }                 swap(a[i][j], a[ll][j]);                 ll++;             }         }     }     else if (n == 2) {         for (int j = 0; j < 4; j++) {             int ll = 3;             for (int i = 3; i >= 0; i--) {                 if (a[i][j] == 0)                     continue;                 if (i - 1 >= 0 && a[i][j] == a[i - 1][j]) {                     a[i][j] *= 2;                     a[i - 1][j] = 0;                 }                 swap(a[i][j], a[ll][j]);                 ll--;             }         }     }     else if (n == 3) {         for (int i = 0; i < 4; i++) {             int ll = 0;             for (int j = 0; j < 4; j++) {                 if (a[i][j] == 0)                     continue;                 if (j + 1 < 4 && a[i][j] == a[i][j + 1]) {                     a[i][j] *= 2;                     a[i][j + 1] = 0;                 }                 swap(a[i][j], a[i][ll]);                 ll++;             }         }     }     else if (n == 4) {         for (int i = 0; i < 4; i++) {             int ll = 3;             for (int j = 3; j >= 0; j--) {                 if (a[i][j] == 0)                     continue;                 if (j - 1 >= 0 && a[i][j] == a[i][j - 1]) {                     a[i][j] *= 2;                     a[i][j - 1] = 0;                 }                 swap(a[i][j], a[i][ll]);                 ll--;             }         }     }     for (int i = 0; i < 4; i++) {         for (int j = 0; j < 4; j++)             cout << a[i][j] << ' ';         cout << endl;     }     system("pause");     return 0; }