Modify framebuffer and NGA framebuffer to read screen size from board model dtb file. Optimise memory usuage of frame buffer
Add example minigui application with hooks to profiler (which writes results to S:\). Modified NGA framebuffer to run its own dfc queue at high priority
#! /usr/bin/env python
"""N queens problem.
The (well-known) problem is due to Niklaus Wirth.
This solution is inspired by Dijkstra (Structured Programming). It is
a classic recursive backtracking approach.
"""
N = 8 # Default; command line overrides
class Queens:
def __init__(self, n=N):
self.n = n
self.reset()
def reset(self):
n = self.n
self.y = [None]*n # Where is the queen in column x
self.row = [0]*n # Is row[y] safe?
self.up = [0] * (2*n-1) # Is upward diagonal[x-y] safe?
self.down = [0] * (2*n-1) # Is downward diagonal[x+y] safe?
self.nfound = 0 # Instrumentation
def solve(self, x=0): # Recursive solver
for y in range(self.n):
if self.safe(x, y):
self.place(x, y)
if x+1 == self.n:
self.display()
else:
self.solve(x+1)
self.remove(x, y)
def safe(self, x, y):
return not self.row[y] and not self.up[x-y] and not self.down[x+y]
def place(self, x, y):
self.y[x] = y
self.row[y] = 1
self.up[x-y] = 1
self.down[x+y] = 1
def remove(self, x, y):
self.y[x] = None
self.row[y] = 0
self.up[x-y] = 0
self.down[x+y] = 0
silent = 0 # If set, count solutions only
def display(self):
self.nfound = self.nfound + 1
if self.silent:
return
print '+-' + '--'*self.n + '+'
for y in range(self.n-1, -1, -1):
print '|',
for x in range(self.n):
if self.y[x] == y:
print "Q",
else:
print ".",
print '|'
print '+-' + '--'*self.n + '+'
def main():
import sys
silent = 0
n = N
if sys.argv[1:2] == ['-n']:
silent = 1
del sys.argv[1]
if sys.argv[1:]:
n = int(sys.argv[1])
q = Queens(n)
q.silent = silent
q.solve()
print "Found", q.nfound, "solutions."
if __name__ == "__main__":
main()