Question

Can someone help me with this program in C++. I would really appreciate your help. Thank You.

Given a 2D board containing 'X' and 'O', capture all regions surrounded by 'X' A region is captured by flipping all 'O's into 'X's in that surrounded region. For example, for the following board, ххXх хоох ххох хох After capturing all regions, the board becomes ХXXX X X X X X X X X хохх The algorithm should take an input file, named "input.txt", and output the resulting board in the console. Sample input.txt 6 хXXXXо хохоох ххооох хххохх хоххо о ХXXXX х The first line is a number indicating the size of the board; in the above example, 6 means the board is 6 x 6. Output for in console: ХXXXX о ХXXXХX ххXXхх ХXXXХX XXXXО О ххXXXх

Answer 1

#include <bits/stdc++.h>
#define fi first
#define se second
const int MAX_SIZE = 200;
using namespace std;

bool containsFreeO(int i, int j, char (&c)[MAX_SIZE][MAX_SIZE], bool (&used1)[MAX_SIZE][MAX_SIZE], int n) {
//Base case
if (i == 0 || j == 0 || i == n - 1 || j == n - 1) {
return true;
}

//Go Up
if (i - 1 >= 0) {
if (!used1[i - 1][j]) {
if (c[i - 1][j] == 'O') {
used1[i - 1][j] = 1;
if (containsFreeO(i - 1, j, c, used1, n)) {
return true;
}
}
}
}

//Go Down
if (i + 1 < n) {
if (!used1[i + 1][j]) {
if (c[i + 1][j] == 'O') {
used1[i + 1][j] = 1;
if (containsFreeO(i + 1, j, c, used1, n)) {
return true;
}
}
}
}

//Go Left
if (j - 1 >= 0) {
if (!used1[i][j - 1]) {
if (c[i][j - 1] == 'O') {
used1[i][j - 1] = 1;
if (containsFreeO(i, j - 1, c, used1, n)) {
return true;
}
}
}
}

//Go Right
if (j + 1 < n) {
if (!used1[i][j + 1]) {
if (c[i][j + 1] == 'O') {
used1[i][j + 1] = 1;
if (containsFreeO(i, j + 1, c, used1, n)) {
return true;
}
}
}
}

return false;

}

void fillWithXes(int i, int j, char (&c)[MAX_SIZE][MAX_SIZE], bool (&used2)[MAX_SIZE][MAX_SIZE], int n) {
c[i][j] = 'X';

//Go Up
if (i - 1 >= 0) {
if (!used2[i - 1][j]) {
if (c[i - 1][j] == 'O') {
used2[i - 1][j] = 1;
fillWithXes(i - 1, j, c, used2, n);
}
}
}

//Go Down
if (i + 1 < n) {
if (!used2[i + 1][j]) {
if (c[i + 1][j] == 'O') {
used2[i + 1][j] = 1;
fillWithXes(i + 1, j, c, used2, n);
}
}
}

//Go Left
if (j - 1 >= 0) {
if (!used2[i][j - 1]) {
if (c[i][j - 1] == 'O') {
used2[i][j - 1] = 1;
fillWithXes(i, j - 1, c, used2, n);
}
}
}

//Go Right
if (j + 1 < n) {
if (!used2[i][j + 1]) {
if (c[i][j + 1] == 'O') {
used2[i][j + 1] = 1;
fillWithXes(i, j + 1, c, used2, n);
}
}
}
}

int main()
{
freopen("input.txt", "r", stdin);

int n;
cin >> n;
char c[MAX_SIZE][MAX_SIZE];
bool used1[MAX_SIZE][MAX_SIZE];
bool used2[MAX_SIZE][MAX_SIZE];

for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
cin >> c[i][j];
used1[i][j] = used2[i][j] = 0;
}
}

vector < pair < int,int > > vc;

for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
if (c[i][j] == 'O')
if (!used1[i][j] && !containsFreeO(i, j, c, used1, n))
vc.push_back({i,j});
}
}

for (int i = 0; i < vc.size(); i++) {
fillWithXes(vc[i].fi, vc[i].se, c, used2, n);
}

for (int i = 0; i < n; i++) {
for (int j = 0; j < n; j++) {
cout << c[i][j] << " ";
}
cout << "\n";
}

return 0;
}

|input.txt Notepad File Edit Format View Help хххXхо хохоох ххооох хххохх хоххоо ххXXXX

ххXXхо хххххх хххххх хххXхх ххXхоо хххххх Process returned @ (Өx0) Press any key to continue. execution time 0.189 s

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