Dch19990825的博客

Loj-1287 Where to Run（状压期望DP）题目链接：LightOJ - 1287 题意：​ 先给一个n个点m条无向边的图，每条边都有一个权值，顶点编号从0开始，刚开始自己站在0号点，现在要躲避警察的追踪。走的路线有如下限制：离开一个顶点之后就不能回到该顶点如果站在某个顶点u，剩下的未走的邻接顶点不存在 E J 顶点就停止并被警察抓到，E J 顶点指如果到该顶点后，...

LOJ-1284 Lights inside 3D Grid（期望，二次项公式奇数项求和）题目链接：传送门题目：在尺寸为X∗Y∗ZX*Y*ZX∗Y∗Z的长方体中每个位置都有一个灯泡，初始没有亮，每次随机取两个点(x1,y1,z1)(x1,y1,z1)(x1,y1,z1),(x2,y2,z2)(x2,y2,z2)(x2,y2,z2)。让所有满足x∈[x1,x2],y∈[y1,y2],z∈[z1...

LOJ 1265-Snakes and Ladders（期望DP+高斯消元）题目链接：[传送门](LightOJ - 1151)其实这道题并不难，写下这篇博客的目的是纪念这种做法，当期望DP方程的递推关系拓扑图有环时，我们可以用高斯消元的方法去做（因为每一个位置都可以列一个方程，且都线性无关，所以可以用高斯消元解方程）题意：有100100100个方格，其中从左到右编号依此为 111 到...

C - Race to 1 AgainRimi learned a new thing about integers, which is - any positive integer greater than 1 can be divided by its divisors. So, he is now playing with this property. He selects a numbe...

B - Discovering GoldYou are in a cave, a long cave! The cave can be represented by a 1 x N grid. Each cell of the cave can contain any amount of gold.Initially you are in position 1. Now each turn y...

A - A Dangerous MazeYou are in a maze; seeing n doors in front of you in beginning. You can choose any door you like. The probability for choosing a door is equal for all doors.If you choose the ith...