Discription The Bad Luck Island is inhabited by three kinds of species: r rocks, s scissors andp papers. At some moments of time two random individuals meet (all pairs of individuals can meet equiprobably), and if they belong to different species, th…

D. Bad Luck Island Time Limit: 1 Sec  Memory Limit: 256 MB 题目连接 http://codeforces.com/contest/540/problem/D Description The Bad Luck Island is inhabited by three kinds of species: r rocks, s scissors and p papers. At some moments of time two random i…

题目链接:https://vjudge.net/contest/226823#problem/D The Bad Luck Island is inhabited by three kinds of species: r rocks, s scissors and p papers. At some moments of time two random individuals meet (all pairs of individuals can meet equiprobably), and i…

题目描述: Bad Luck Island time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The Bad Luck Island is inhabited by three kinds of species: r rocks, s scissors and p papers. At some moments of time…

D. Bad Luck Island time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The Bad Luck Island is inhabited by three kinds of species: r rocks, s scissors and p papers. At some moments of time two…

D. Bad Luck Island time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The Bad Luck Island is inhabited by three kinds of species: r rocks, s scissors and p papers. At some moments of time two…

D:Bad Luck Island 一个岛上有r个石头,s个剪子,p个布,他们之间随机挑出两个相遇,如果不是相同物种,就会有一个消失,分别求出最后这座岛上只剩下一个物种的概率. 我们用dp[i][j][k]来存储剩下 i 个石头, j 个剪刀,k 个布时的概率,共dp三次: 如果石头与剪刀碰面,概率是 p1 = i*j / (i*j+j*k+k*i),这种情况下,剪刀会被石头吃掉,所以石头的数目减少1,表现出来是dp[i-1][j][k] = p1*dp[i][j][k]  (dp的3的返回值均…

Bad Luck Island time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output The Bad Luck Island is inhabited by three kinds of species: r rocks, s scissors and p papers. At some moments of time two ra…

http://codeforces.com/problemset/problem/540/D 题目大意: 会出石头.剪刀.布的人分别有r,s,p个,他们相互碰到的概率相同,输的人死掉,问最终活下去的人是三种类型的概率. 思路: f[i][j][k]代表i个石头,j个剪刀,k个布状态的概率,初始f[n][m][K]=1 #include<cstdio> #include<cmath> #include<algorithm> #include<cstring>…

题意与分析(CodeForces 540D) 是一道概率dp题. 不过我没把它当dp做... 我就是凭着概率的直觉写的,还好这题不算难. 这题的重点在于考虑概率:他们喜相逢的概率是多少?考虑超几何分布的变形:\[P=\frac{C^1_aC^1_b}{C^2_{a+b+c}-\frac{a(a-1)}{2}-\frac{b(b-1)}{2}-\frac{c(c-1)}{2}}=\frac{ab}{ab+bc+ac}\]即可. 最后还有求和的操作需要注意一下(因为我们没考虑\(i,j,k\)为0的…