nqueen

PHOTO EMBED

Fri Jul 02 2021 17:34:27 GMT+0000 (Coordinated Universal Time)

Saved by @rushi #c++

#include<iostream>
using namespace std;
bool issafe(int** arr,int x,int y,int n){
    for(int row=0;row<=x;row++){
        if(arr[x][y]==1){
            return false;
        }
    }
    int row=x;
    int col=y;
    while(row>=0 && col>=0){
        if(arr[row][col]==1){
            return false;
        }
        row--;
        col--;
    }
     row=x;
     col=y;
    while(row>=0 && col<n){
        if(arr[row][col]==1){
            return false;
        }
        row--;
        col++;
    }
    return true ;
}
bool nqueen(int** arr,int x,int n){
    if(x>=n){
        return true;
    }
    for(int col=0;col<=n;col++){
        if(issafe(arr,x,col,n)){
            arr[x][col]==1;
            if(nqueen(arr,x+1,n)){
                return true;
            }
            arr[x][col]=0;  //backtracking
            
        }
    }
    return false;
}
int main(){
    int n;
    cin>>n;
    int** arr=new int*[n];
    for(int i=0;i<n;i++){
        arr[i]=new int[n];
        for(int j=0;j<n;j++){
            arr[i][j]=0;

        }
    }
    if(nqueen(arr,0,n)){
        for(int i=0;i<n;i++){
            for(int j=0;j<n;j++){
                cout<<arr[i][j]<<"";
            }cout<<endl;
        }
    }


    return 0;
}
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