From a83e44ea6c6b5c2e979ffcb9b4c1c8aa2a942c55 Mon Sep 17 00:00:00 2001 From: Sombit Bose Date: Wed, 29 Apr 2020 22:11:47 +0530 Subject: [PATCH 1/5] Create n_queens_all_solution_optimised.cpp --- .../n_queens_all_solution_optimised.cpp | 86 +++++++++++++++++++ 1 file changed, 86 insertions(+) create mode 100644 backtracking/n_queens_all_solution_optimised.cpp diff --git a/backtracking/n_queens_all_solution_optimised.cpp b/backtracking/n_queens_all_solution_optimised.cpp new file mode 100644 index 000000000..f8da31c4f --- /dev/null +++ b/backtracking/n_queens_all_solution_optimised.cpp @@ -0,0 +1,86 @@ +#include +#define n 4 +#define inc_loop(var,start,stop,step) for(int var=start;var<=stop;var+=step) +#define dec_loop(var,start,stop,step) for(int var=start;var>=stop;var-=step) + +void PrintSol(int Board[n][n]) +{ + inc_loop(i,0,n-1,1) + { + inc_loop(j,0,n-1,1) + std::cout << Board[i][j] << " "; + std::cout << std::endl; + } + std::cout << std::endl; + if (n%2==0 || (n%2==1 && Board[n/2+1][0]!=1)) + { + inc_loop(i,0,n-1,1) + { + dec_loop(j,n-1,0,1) + std::cout<= 0 && j >= 0; i--, j--) { + if (Board[i][j] == 1) + return false; + } + /// check the second diagonal + for (int i = row, j = col; i <= n - 1 && j >= 0; i++, j--) { + if (Board[i][j] == 1) + return false; + } + return true; +} + +void NQueenSol(int Board[n][n], int col) { + if (col >= n) { + PrintSol(Board); + return; + } + inc_loop(i,0,n-1,1) + { + if (CanIMove(Board, i, col)) { + Board[i][col] = 1; + NQueenSol(Board, col + 1); + Board[i][col] = 0; + } + } +} + +int main() { + int Board[n][n] = {0}; + if (n%2==0) + { + inc_loop(i,0,n/2-1,1) + { + if (CanIMove(Board, i, 0)) { + Board[i][0] = 1; + NQueenSol(Board,1); + Board[i][0] = 0; + } + } + } + else + { + inc_loop(i,0,n/2,1) + { + if (CanIMove(Board, i,0)) { + Board[i][0] = 1; + NQueenSol(Board,1); + Board[i][0] = 0; + } + } + } + return 0; +} From b8bcd82c2661cfb1bacd7c4e8e3fe87840cadb28 Mon Sep 17 00:00:00 2001 From: Sombit Bose Date: Wed, 29 Apr 2020 22:39:35 +0530 Subject: [PATCH 2/5] update --- backtracking/n_queens_all_solution_optimised.cpp | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/backtracking/n_queens_all_solution_optimised.cpp b/backtracking/n_queens_all_solution_optimised.cpp index f8da31c4f..62226cd3f 100644 --- a/backtracking/n_queens_all_solution_optimised.cpp +++ b/backtracking/n_queens_all_solution_optimised.cpp @@ -1,7 +1,7 @@ #include #define n 4 -#define inc_loop(var,start,stop,step) for(int var=start;var<=stop;var+=step) -#define dec_loop(var,start,stop,step) for(int var=start;var>=stop;var-=step) +#define inc_loop(var, start, stop, step) for (int var=start; var <= stop; var+=step) +#define dec_loop(var, start, stop, step) for (int var=start; var >= stop; var-=step) void PrintSol(int Board[n][n]) { From c76eb387ac022f79c24f813703d054d8778454fe Mon Sep 17 00:00:00 2001 From: Sombit Bose Date: Wed, 29 Apr 2020 22:42:56 +0530 Subject: [PATCH 3/5] update --- .../n_queens_all_solution_optimised.cpp | 28 ++++++------------- 1 file changed, 9 insertions(+), 19 deletions(-) diff --git a/backtracking/n_queens_all_solution_optimised.cpp b/backtracking/n_queens_all_solution_optimised.cpp index 62226cd3f..40056100d 100644 --- a/backtracking/n_queens_all_solution_optimised.cpp +++ b/backtracking/n_queens_all_solution_optimised.cpp @@ -2,20 +2,15 @@ #define n 4 #define inc_loop(var, start, stop, step) for (int var=start; var <= stop; var+=step) #define dec_loop(var, start, stop, step) for (int var=start; var >= stop; var-=step) - -void PrintSol(int Board[n][n]) -{ - inc_loop(i,0,n-1,1) - { +void PrintSol(int Board[n][n]) { + inc_loop(i,0,n-1,1) { inc_loop(j,0,n-1,1) std::cout << Board[i][j] << " "; std::cout << std::endl; } std::cout << std::endl; - if (n%2==0 || (n%2==1 && Board[n/2+1][0]!=1)) - { - inc_loop(i,0,n-1,1) - { + if (n%2==0 || (n%2==1 && Board[n/2+1][0]!=1)){ + inc_loop(i,0,n-1,1){ dec_loop(j,n-1,0,1) std::cout< Date: Wed, 29 Apr 2020 22:49:20 +0530 Subject: [PATCH 4/5] update --- .../n_queens_all_solution_optimised.cpp | 37 +++++++++---------- 1 file changed, 18 insertions(+), 19 deletions(-) diff --git a/backtracking/n_queens_all_solution_optimised.cpp b/backtracking/n_queens_all_solution_optimised.cpp index 40056100d..2c1e4a84a 100644 --- a/backtracking/n_queens_all_solution_optimised.cpp +++ b/backtracking/n_queens_all_solution_optimised.cpp @@ -1,27 +1,27 @@ #include #define n 4 -#define inc_loop(var, start, stop, step) for (int var=start; var <= stop; var+=step) -#define dec_loop(var, start, stop, step) for (int var=start; var >= stop; var-=step) +#define inc_loop(var, start, stop) for (int var=start; var <= stop; var++) +#define dec_loop(var, start, stop) for (int var=start; var >= stop; var--) void PrintSol(int Board[n][n]) { - inc_loop(i,0,n-1,1) { - inc_loop(j,0,n-1,1) + inc_loop(i,0,n-1) { + inc_loop(j,0,n-1) std::cout << Board[i][j] << " "; std::cout << std::endl; } std::cout << std::endl; - if (n%2==0 || (n%2==1 && Board[n/2+1][0]!=1)){ - inc_loop(i,0,n-1,1){ - dec_loop(j,n-1,0,1) - std::cout< Date: Wed, 29 Apr 2020 22:52:44 +0530 Subject: [PATCH 5/5] update --- backtracking/n_queens_all_solution_optimised.cpp | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) diff --git a/backtracking/n_queens_all_solution_optimised.cpp b/backtracking/n_queens_all_solution_optimised.cpp index 2c1e4a84a..1db730f63 100644 --- a/backtracking/n_queens_all_solution_optimised.cpp +++ b/backtracking/n_queens_all_solution_optimised.cpp @@ -3,15 +3,15 @@ #define inc_loop(var, start, stop) for (int var=start; var <= stop; var++) #define dec_loop(var, start, stop) for (int var=start; var >= stop; var--) void PrintSol(int Board[n][n]) { - inc_loop(i,0,n-1) { - inc_loop(j,0,n-1) + inc_loop(i, 0, n-1) { + inc_loop(j, 0, n-1) std::cout << Board[i][j] << " "; std::cout << std::endl; } std::cout << std::endl; - if (n%2 == 0 || (n%2 == 1 && Board[n/2+1][0] != 1)){ - inc_loop(i,0,n-1){ - dec_loop(j,n-1,0) + if (n%2 == 0 || (n%2 == 1 && Board[n/2+1][0] != 1)) { + inc_loop(i, 0, n-1) { + dec_loop(j, n-1, 0) std::cout << Board[i][j] << " "; std::cout << std::endl; } @@ -21,7 +21,7 @@ void PrintSol(int Board[n][n]) { bool CanIMove(int Board[n][n], int row, int col) { /// check in the row - inc_loop (i, 0, col-1) { + inc_loop(i, 0, col-1) { if (Board[row][i] == 1) return false; } @@ -43,7 +43,7 @@ void NQueenSol(int Board[n][n], int col) { PrintSol(Board); return; } - inc_loop(i,0,n-1,1) { + inc_loop(i, 0, n-1) { if (CanIMove(Board, i, col)) { Board[i][col] = 1; NQueenSol(Board, col + 1);