import random def evaluate(x1, x2, x3):     return x1+x2-x3 if __name__ == '__main__':     x_range = [ [-2, 5], [2, 6], [-5, 2] ]     best_sol = [random.randint(x_range[0][0], x_range[0][1]),            random.randint(x_range[1][0], x_range[1][1]),            random.randint(x_range[2][0], x_range[2][1])]     while True:         best_evaluate = evaluate(best_sol[0], best_sol[1], best_sol[2])         current_best_value = best_evaluate         sols = [best_sol]         for i in xrange(len(best_sol)):             if best_sol[i] > x_range[i][0]:                 sols.append(best_sol[0:i] + [best_sol[i]-1] + best_sol[i+1:])             if best_sol[i] < x_range[i][1]:                 sols.append(best_sol[0:i] + [best_sol[i]+1] + best_sol[i+1:])         print sols         for s in sols:             el = evaluate(s[0], s[1], s[2])             if el < best_evaluate:                 best_sol = s                 best_evaluate = el         if best_evaluate == current_best_value:             break     print 'best sol：', current_best_value, best_sol 某次运行结果如下： [[0, 5, 1], [-1, 5, 1], [1, 5, 1], [0, 4, 1], [0, 6, 1], [0, 5, 0], [0, 5, 2]] [[-1, 5, 1], [-2, 5, 1], [0, 5, 1], [-1, 4, 1], [-1, 6, 1], [-1, 5, 0], [-1, 5, 2]] [[-2, 5, 1], [-1, 5, 1], [-2, 4, 1], [-2, 6, 1], [-2, 5, 0], [-2, 5, 2]] [[-2, 4, 1], [-1, 4, 1], [-2, 3, 1], [-2, 5, 1], [-2, 4, 0], [-2, 4, 2]] [[-2, 3, 1], [-1, 3, 1], [-2, 2, 1], [-2, 4, 1], [-2, 3, 0], [-2, 3, 2]] [[-2, 2, 1], [-1, 2, 1], [-2, 3, 1], [-2, 2, 0], [-2, 2, 2]] [[-2, 2, 2], [-1, 2, 2], [-2, 3, 2], [-2, 2, 1]] best sol： -2 [-2, 2, 2]