# 比赛链接

https://codeforces.com/contest/1555

# 1. A. PizzaForces

## 1.1. 题意

6元15个物品，8元20个物品，10元25个物品

## 1.2. 做法

notes: 注意一定是至少两倍以上才能贪心

# 比赛链接

https://codeforces.com/contest/1551

# 比赛链接

VK Cup 2021 - Elimination (Engine)

# 题目大意：

$inv$ 为逆序对个数

# 做法：

$f(i,j) = \sum_{t \in [1,i]} f(i-1,j-t+1)$

\begin{aligned} ans[i] \&= i * ans[i-1] + \sum_{1<=u<v<=i, x+u>y+v} f(i-1,x)\cdot f(i-1,y) \&= i * ans[i-1] + \sum_{x-y>v-u, 1<=u<v<=i} f(i-1,x)\cdot f(i-1,y) \&= i * ans[i-1] + \sum_{x-y>d, 1<=d<i} (i-d)*f(i-1,x)\cdot f(i-1,y) \&= i * ans[i-1] + \sum_{x,y} f(i-1,x)\cdot f(i-1,y) \cdot \sum_{x-y>d, 1<=d<i} (i-d) \end{aligned}

## Codeforces Round #172 (Div. 1) - D

nexthexonextbutterflyvolantisyearnyiliashokaindigoapollolandscapecactusmateryicarusfluidmaterial namek-Maximum Subsequence Sum descirptiontime limit per test 4 secondsmemory limit per test 256 meg...

## Codeforces Round ##FF (Div. 1) - C

nexthexonextbutterflyvolantisyearnyiliashokaindigoapollolandscapecactusmateryicarusfluidmaterial nameDZY Loves Fibonacci Numbers discriptiontime limit per test:4 secondsmemory limit per test:256 m...

## Educational Codeforces Round 60 (Rated for Div. 2) - D

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