1) Give a solution for the 4 queens problem (you do not need to draw the grid, just say where you will place the queens)

2) Refer to figure 2.2 (the algorithm) and explain the lines of code of this algorithm.

PLACEQUEENS(Q[1..n),r): if r=n+1 print Q[1..n] else for j - 1 ton legal TRUE for i = 1 tor-1 if (Q[i]=j) or (Q[i]=j+r-i) or (Q[i]=j-r+i) legal FALSE if legal Q[r]; PLACEQUEENS(Q[1..n],r+1) ((Recursion!>> Figure 2.2. Gauss and Laquire's backtracking algorithm for the n queens