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Timus 1996 Cipher Message 3 KMP+FFT求卷积

题目链接:click here


Emperor Palpatine has been ruling the Empire for 25 years and Darth Vader has been the head of the Empire Armed Forces. However, the Rebel movement is strong like it never used to be. One of the rebel leaders, Princess Leia from Alderaan, managed to get hold of secret blueprints of the Death Star, the imperial war station.

The Princess was going to deliver the station plan to the secret base for further analysis and searching for vulnerable spots. But her ship was attacked by the space destroyer "Devastator" headed by Darth Vader. At the last moment Princess Leia managed to send her findings to one of the closest planet called Tatooine with her droid R2-D2. Quite conveniently, an old friend of her father Obi-Wan Kenobi lives on that planet.

R2-D2 realizes the importance of his mission. He is going to encrypt the information so that the wrong people won’t get it.





ACM International Collegiate Programming Contest Asia Regional Contest, Tokyo Problem D Space Golf

原题 pdf:click here

日本的亚洲区域赛真心简单啊。两个小时就刷了 5 题有余了。排名第一的队伍才做出 7 道。


题意其实也就是太空中向前方抛小球,问小球能够穿过 N 个障碍物后到达制定地点的最小初始速度是多少。非常暴力的模拟题。离散化后直接枚举弹跳的次数再取最小值即可。注意 45° 方向能成功的话,那还是 45° 最优。





1.字体:infinally 渲染

2.英文字体:courier prime



HDU 4965 Fast Matrix Calculation

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 131072/131072 K (Java/Others) Total Submission(s): 206    Accepted Submission(s): 116

Problem Description
One day, Alice and Bob felt bored again, Bob knows Alice is a girl who loves math and is just learning something about matrix, so he decided to make a crazy problem for her. Bob has a six-faced dice which has numbers 0, 1, 2, 3, 4 and 5 on each face. At first, he will choose a number N (4 <= N <= 1000), and for N times, he keeps throwing his dice for K times (2 <=K <= 6) and writes down its number on the top face to make an N*K matrix A, in which each element is not less than 0 and not greater than 5\. Then he does similar thing again with a bit difference: he keeps throwing his dice for N times and each time repeat it for K times to write down a K*N matrix B, in which each element is not less than 0 and not greater than 5\. With the two matrix A and B formed, Alice’s task is to perform the following 4-step calculation.

HDU 4945 2048

Time Limit: 3000/1500 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 590    Accepted Submission(s): 136

Problem Description
Teacher Mai is addicted to game 2048\. But finally he finds it's too hard to get 2048\. So he wants to change the rule: You are given some numbers. Every time you can choose two numbers of the same value from them and merge these two numbers into their sum. And these two numbers disappear meanwhile. If we can get 2048 from a set of numbers with this operation, Teacher Mai think this multiset is good. You have n numbers, A1,...,An. Teacher Mai ask you how many subsequences of A are good. The number can be very large, just output the number modulo 998244353.

HDU 4952 Number Transformation

Time Limit: 2000/1000 MS (Java/Others)    Memory Limit: 65536/65536 K (Java/Others) Total Submission(s): 612    Accepted Submission(s): 310

Problem Description
Teacher Mai has an integer x. He does the following operations k times. In the i-th operation, x becomes the least integer no less than x, which is the multiple of i. He wants to know what is the number x now.