Prototype Pattern will use object instance to create a new same object instance. So in this way, the two instance has some relationship like this:

Singleton Pattern is a kind of design pattern which used to keep a object unique. For every user who want to use this class to create a object, he should get the same one. Singleton pattern could be used in many scenarios:

Web failure rate analysis（divide and conquer ）

473. Matchsticks to Square

4. Median of Two Sorted Arrays

376. Wiggle Subsequence

416. Partition Equal Subset Sum

Classic 0-1 Knapsack probles. Use two dimension array dp[i][j] to represent that end at i-th element can find the sum j.

218. The Skyline Problem

93. Restore IP Addresses

Composition Mod

power (a , b) % m in O(n)

For every number b, we have the representation of b in this way: