CF803E.Roma and Poker
普及/提高-
通过率:0%
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题目描述
Each evening Roma plays online poker on his favourite website. The rules of poker on this website are a bit strange: there are always two players in a hand, there are no bets, and the winner takes 1 virtual bourle from the loser.
Last evening Roma started to play poker. He decided to spend no more than k virtual bourles — he will stop immediately if the number of his loses exceeds the number of his wins by k . Also Roma will leave the game if he wins enough money for the evening, i.e. if the number of wins exceeds the number of loses by k .
Next morning Roma found a piece of paper with a sequence on it representing his results. Roma doesn't remember the results exactly, and some characters in the sequence are written in a way such that it's impossible to recognize this character, so Roma can't recall whether he won k bourles or he lost.
The sequence written by Roma is a string s consisting of characters W (Roma won the corresponding hand), L (Roma lost), D (draw) and ? (unknown result). Roma wants to restore any valid sequence by changing all ? characters to W, L or D. The sequence is called valid if all these conditions are met:
- In the end the absolute difference between the number of wins and loses is equal to k ;
- There is no hand such that the absolute difference before this hand was equal to k .
Help Roma to restore any such sequence.
输入格式
The first line contains two numbers n (the length of Roma's sequence) and k ( 1<=n,k<=1000 ).
The second line contains the sequence s consisting of characters W, L, D and ?. There are exactly n characters in this sequence.
输出格式
If there is no valid sequence that can be obtained from s by replacing all ? characters by W, L or D, print NO.
Otherwise print this sequence. If there are multiple answers, print any of them.
输入输出样例
输入#1
3 2 L??
输出#1
LDL
输入#2
3 1 W??
输出#2
NO
输入#3
20 5 ?LLLLLWWWWW?????????
输出#3
WLLLLLWWWWWWWWLWLWDW