递归代码模板
public void recur(int level, int param) {
// terminator
if (level > MAX_LEVEL) {
// process result
return;
}
// process current logic
process(level, param);
// drill down
recur( level: level + 1, newParam);
// restore current status
}分治代码模板
def divide_conquer(problem, param1, param2, ...):
# recursion terminator
if problem is None:
print_result
return
# prepare data
data = prepare_data(problem)
subproblems = split_problem(problem, data)
# conquer subproblems
subresult1 = self.divide_conquer(subproblems[0], p1, ...)
subresult2 = self.divide_conquer(subproblems[1], p1, ...)
subresult3 = self.divide_conquer(subproblems[2], p1, ...)
…
# process and generate the final result
result = process_result(subresult1, subresult2, subresult3, …)
# revert the current level states- 人肉递归低效
- 拆解成可重复解决的问题
- 数学归纳法
It refers to simplifying a complicated problem by breaking it down into simpler sub-problems in a recursive manner.
将复杂问题以递归方式分解为简单子问题。
动态规划和递归或者分治没有根本上的区别（关键看有无最优子结构）
共性：找到重复子问题
差异性：最优子结构、中途可以淘汰次优解