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1.1. Enumeration algorithm
1.1.1. Algorithm definition
In inductive reasoning , If you examine all possible situations of a certain type of event one by one , Therefore, a general conclusion is drawn , Then the conclusion is reliable , This method of induction is called enumeration .
1.1.2. The basic idea
The basic idea of enumeration algorithm is , List all the possible answers to the question , Judge one by one according to the conditions , Choose the answer that meets your needs . The design steps are ：
（1） Select the appropriate range of research objects .
（2） Find the condition to judge the correct solution .
（3） Examine all subjects in the scope one by one
The execution process is as follows ： 
The idea of this algorithm is simple , Easy to understand , The correctness of the algorithm is easy to prove ; But when the enumeration range is large , According to different conditions , It will be inefficient in some cases .
1.1.3. Algorithm example -- A hundred dollars for a hundred chickens
Problem description ：
Each cock 5 element , Each hen 3 element , Three chicks 1 element , use 100 Yuan to buy 100 chicken , Ask the rooster 、 hen 、 How many chickens each ？
Algorithm analysis ：
The enumeration method is used to solve this problem , Take the number of three kinds of chickens as the enumeration object , Set as mj、gj and xj, Use the total number of three kinds of chickens （mj+gj+xj=100） And the total amount of money for chicken （gj5+mj3+xj/3==100） As a judgment condition , List the number of chickens . Among them, the rooster 5 element / only , You can buy at most 20 A rooster ; hen 3 element / only , You can buy at most 33 A hen ; Chick 1 element / only , You can buy at most 100 only .
Code implementation ：
【 example 1-1】 A hundred dollars for a hundred chickens ：
for gj in range(0,23):\
for mj in range(0,34):\
xj = 100-gj-mj\
if xj%3==0 and gj*5+mj*3+xj/3==100:\
print("100 Yuan can buy a rooster ：{}, hen ：{}, Chick ：{}".format(gj, mj, xj))
Execution results :
100 Yuan can buy a rooster ：0, hen ：25, Chick ：75
100 Yuan can buy a rooster ：4, hen ：18, Chick ：78
100 Yuan can buy a rooster ：8, hen ：11, Chick ：81
100 Yuan can buy a rooster ：12, hen ：4, Chick ：84
