New Commit

Author: coder-mayank22

N_Queen.c

@@ -0,0 +1,67 @@
+#include<stdio.h>
+// #define BOARD_SIZE 5
+int n;
+
+void input(){
+    printf("Enter the value of n: ");
+    scanf("%d", &n);
+}
+void displayChess(int chBoard[n][n]) {
+   for (int row = 0; row < n; row++) {
+      for (int col = 0; col < n; col++)
+         printf("%d ", chBoard[row][col]);
+      printf("\n");
+   }
+}
+int isQueenPlaceValid(int chBoard[n][n], int crntRow, int crntCol) {
+   // checking if queen is in the left or not    
+   for (int i = 0; i < crntCol; i++)    
+      if (chBoard[crntRow][i])
+         return 0;
+   for (int i = crntRow, j = crntCol; i >= 0 && j >= 0; i--, j--)
+      //checking if queen is in the left upper diagonal or not
+      if (chBoard[i][j])       
+         return 0;
+   for (int i = crntRow, j = crntCol; j >= 0 && i < n; i++, j--)
+      //checking if queen is in the left lower diagonal or not
+      if (chBoard[i][j])      
+         return 0;
+   return 1;
+}
+int solveProblem(int chBoard[n][n], int crntCol) {
+   //when N queens are placed successfully
+   if (crntCol >= n)           
+      return 1;
+   // checking placement of queen is possible or not
+   for (int i = 0; i < n; i++) {     
+      if (isQueenPlaceValid(chBoard, i, crntCol)) {
+         //if validate, place the queen at place (i, col)
+         chBoard[i][crntCol] = 1;     
+         //Go for the other columns recursively
+         if (solveProblem(chBoard, crntCol + 1))    
+            return 1;          
+         //When no place is vacant remove that queen   
+         chBoard[i][crntCol] = 0;        
+      }
+   }
+   return 0;      
+}
+int displaySolution() {
+   int chBoard[n][n];
+   for(int i = 0; i < n; i++)
+      for(int j = 0; j < n; j++)
+         //set all elements to 0
+         chBoard[i][j] = 0;      
+   //starting from 0th column
+   if (solveProblem(chBoard, 0) == 0) {     
+      printf("Solution does not exist");
+      return 0;
+   }
+   displayChess(chBoard);
+   return 1;
+}
+int main() {
+    input();
+   displaySolution();
+   return 0;
+}