Initial commit

Author: phoenixx1

Backtracking/No.OfIsland.cpp

@@ -0,0 +1,68 @@
+//author @Nishant
+
+#include<bits/stdc++.h>
+using namespace std;
+
+int totalBridges(int **mat, int n, int m);
+void removeIsland(int **mat, int n, int m, int i, int j);
+bool isSafe(int n, int m, int i, int j);
+
+int main(){
+    int m, n;
+    cin >> n >> m;
+    int **mat = (int **)malloc(n * sizeof(int *));
+    for(int i=0; i<n; i++){
+        mat[i] = (int *)malloc(m * sizeof(int));
+    }
+    for(int i=0; i<n; i++){
+        for(int j=0; j<m; j++){
+            cin >> mat[i][j];
+        }
+    }
+    // for(int i=0; i<m; i++){
+    //     cout << endl;
+    //     for(int j=0; j<n; j++){
+    //         cout << mat[i][j] << "\t";
+    //     }
+    // }
+    cout << totalBridges(mat, n, m);
+    return 0;
+}
+
+int totalBridges(int **mat, int n, int m){
+    int count = 0;
+    //cout << mat[0][0] << endl;
+    for(int i=0; i<n; i++){
+        for(int j=0; j<m; j++){
+            if(mat[i][j] == 1){
+                count++;
+                removeIsland(mat, n, m, i, j);
+            }
+        }
+    }
+    return count - 1;
+}
+
+void removeIsland(int **mat, int n, int m, int i, int j){
+    if(isSafe(n, m, i, j) && mat[i][j]==1){
+        mat[i][j] = 0;
+        removeIsland(mat, n, m, i - 1, j - 1);
+        removeIsland(mat, n, m, i - 1, j);
+        removeIsland(mat, n, m, i - 1, j + 1);
+        removeIsland(mat, n, m, i, j - 1);
+        removeIsland(mat, n, m, i, j + 1);
+        removeIsland(mat, n, m, i + 1, j - 1);
+        removeIsland(mat, n, m, i + 1, j);
+        removeIsland(mat, n, m, i + 1, j + 1);
+    }
+}
+
+bool isSafe(int n, int m, int i, int j){
+    if(i<0 || i>=n){
+        return false;
+    }
+    if(j<0 || j>=m){
+        return false;
+    }
+    return true;
+}

Backtracking/RatNMaze.cpp

@@ -0,0 +1,66 @@
+//author @Nishant
+
+#include<bits/stdc++.h>
+using namespace std;
+
+void showPath(int **sol, int N) {
+   for (int i = 0; i < N; i++) {
+      for (int j = 0; j < N; j++)
+         cout << " " << sol[i][j] << " ";
+      cout << endl;
+   }
+}
+
+bool isValidPlace(int **mat, int N, int x, int y) {      //function to check place is inside the maze and have value 1
+   if(x >= 0 && x < N && y >= 0 && y < N && mat[x][y] == 1)
+      return true;
+   return false;
+}
+
+bool solveRatMaze(int **sol, int **mat, int N, int x, int y) {
+   if(x == N-1 && y == N-1) {       //when (x,y) is the bottom right room
+      sol[x][y] = 1;
+      return true;
+   }
+
+   if(isValidPlace(mat, N, x, y) == true) {     //check whether (x,y) is valid or not
+      sol[x][y] = 1; //set 1, when it is valid place
+      if (solveRatMaze(sol, mat, N, x+1, y) == true)       //find path by moving right direction
+         return true;
+      if (solveRatMaze(sol, mat, N, x, y+1) == true)         //when x direction is blocked, go for bottom direction
+         return true;
+      sol[x][y] = 0;         //if both are closed, there is no path
+      return false;
+   }  
+   return false;
+}
+
+bool findSolution(int **sol, int **mat, int N) {
+   if(solveRatMaze(sol, mat, N, 0, 0) == false) {
+      cout << "There is no path";
+      return false;
+   }
+   cout << "\nPath to get out of maze" << endl;
+   showPath(sol, N);
+   return true;
+}
+
+int main() {
+    int N;
+    cout << "Enter n value:";
+    cin >> N;
+    int **mat = (int **)malloc(N * sizeof(int *));
+    for(int i=0; i<N; i++){
+        mat[i] = (int *)malloc(N * sizeof(int));
+    }
+    int **sol = (int **)malloc(N * sizeof(int *));
+    for(int i=0; i<N; i++){
+        sol[i] = (int *)malloc(N * sizeof(int));
+    }
+    for(int i=0; i<N; i++){
+        for(int j=0; j<N; j++){
+            cin >> mat[i][j];
+        }
+    }
+    findSolution(sol, mat, N);
+}