随笔分类 -  概率期望

摘要:题意: 给个有向图,每个节点等概率转移到它的后继节点,现在问一些节点的期望访问次数; 思路: 对于一个点v,Ev=Ea/d[a]+Eb/d[b]+Ec/d[c];a,b,c是v的前驱节点; 然后按这个列出方程,进行高斯约旦消元,然后判断是否可达和是否为0; 代码是白书上的; AC代码: 阅读全文
posted @ 2016-09-05 22:41 LittlePointer 阅读(277) 评论(0) 推荐(0) 编辑
摘要:题目链接: E. ZS and The Birthday Paradox、 time limit per test 2 seconds memory limit per test 256 megabytes input standard input output standard output ti 阅读全文
posted @ 2016-08-31 16:13 LittlePointer 阅读(511) 评论(0) 推荐(0) 编辑
摘要:题目链接: Hearthstone Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others) Problem Description Hearthstone is an online collec 阅读全文
posted @ 2016-08-10 23:33 LittlePointer 阅读(436) 评论(0) 推荐(0) 编辑
摘要:题目链接: Balls and Boxes Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others) Problem Description Mr. Chopsticks is intereste 阅读全文
posted @ 2016-08-09 23:27 LittlePointer 阅读(488) 评论(0) 推荐(0) 编辑
摘要:题目链接: NanoApe Loves Sequence Time Limit: 2000/1000 MS (Java/Others) Memory Limit: 262144/131072 K (Java/Others) Problem Description NanoApe, the Retir 阅读全文
posted @ 2016-08-06 23:35 LittlePointer 阅读(250) 评论(0) 推荐(0) 编辑
摘要:题目链接: ATM Mechine Time Limit: 6000/3000 MS (Java/Others) Memory Limit: 65536/65536 K (Java/Others) Problem Description Alice is going to take all her 阅读全文
posted @ 2016-08-03 10:57 LittlePointer 阅读(492) 评论(0) 推荐(0) 编辑

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