Divide and conquer strategy for algorithm design and analysis

Where to govern the crowd is like governing the widow, the score is also. ------"The Art of War"

Basic idea of ​​divide and conquer strategy

Divide a big problem that is difficult to solve directly into some smaller, same problems , so that they can be defeated and divided and conquered.

Algorithm design pattern of divide and conquer strategy

Divide_and_Conquer(P){
    
    
	if (|P|＜＝n0 ) return adhoc(P)；
	divide P into smaller substances P1，P2，…，Pk；
	for (i＝1; i＜＝k; k＋＋) 
		yi＝Divide_and_Conquer(Pi)	     //递归解决Pi
	Return merge(y1，y2，…，yk)	    //合并子问题
}

Characteristics of problems that can be solved by divide and conquer strategies

1. The size of the problem can be easily solved by reducing it to a certain extent
2. The problem can be decomposed into several smaller, identical problems
3. The solutions of the sub-problems decomposed by the problem can be combined into the solution of the problem
4. The sub-problems decomposed by the problem are independent of each other

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