172. Snowball Fight

Codeforces

IDCF10269172

Time1000ms

Memory256MB

Difficulty—

English · Original

Formal · Original

You're tired of the warm July weather, so you and your friends decide to take a trip to Antarctica, and have a snowball fight. Each person is given a very large number of snowballs (essentially, an infinite number). Each person is also wearing a coat with a certain color, and boots with a certain color. Throughout the snowball fight, each person throws their snowballs at everyone else who doesn't either have the same color of coat, or the same color of boots, exactly once. Obviously, people don't throw snowballs at themselves. Given this information, figure out how many snowballs are thrown in total during the snowball fight. The first line of input consists of a single positive integer $n$: the number of people involved in the snowball fight. The next line of input consists of $n$ space-separated strings: the coat color of each person involved in the snowball fight, in order. The next line of input consists of $n$ space-separated strings: the boot color of each person involved in the snowball fight, in order. Output a single positive integer $n$: the total number of snowballs that are thrown during the snowball fight. ## Input The first line of input consists of a single positive integer $n$: the number of people involved in the snowball fight.The next line of input consists of $n$ space-separated strings: the coat color of each person involved in the snowball fight, in order.The next line of input consists of $n$ space-separated strings: the boot color of each person involved in the snowball fight, in order. ## Output Output a single positive integer $n$: the total number of snowballs that are thrown during the snowball fight. [samples]

**Definitions** Let $ n \in \mathbb{Z}^+ $ be the number of people. Let $ C = (c_1, c_2, \dots, c_n) $ be the sequence of coat colors. Let $ B = (b_1, b_2, \dots, b_n) $ be the sequence of boot colors. **Constraints** For all $ i, j \in \{1, \dots, n\} $, person $ i $ throws a snowball to person $ j $ if and only if: - $ i \ne j $, - $ c_i \ne c_j $, - $ b_i \ne b_j $. **Objective** Compute the total number of snowballs thrown: $$ \sum_{i=1}^{n} \sum_{\substack{j=1 \\ j \ne i \\ c_i \ne c_j \\ b_i \ne b_j}}^{n} 1 $$

API Response (JSON)

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