시간 제한메모리 제한제출정답맞힌 사람정답 비율
1 초 128 MB48881492112927.753%

문제

상근이는 오디션 프로그램 대한민국 아이돌의 예선에 참가중이다.

대한민국 아이돌 오디션 프로그램에서 참가자는 심사위원에게 10분동안 자신의 매력을 발산할 기회를 갖는다. 모든 참가자가 경연이 끝난후에, 심사위원은 모두 모여서 투표를 하게 된다. 각 심사위원은 다음 라운드에 꼭 진출시켰으면 하는 사람(찬성)이나 이번 라운드에서 꼭 탈락시켰으면 하는 사람(반대)을 두 명 고른다. 한 심사위원이 찬성표를 두 개 내는 것과 반대표를 두 개 내는 것도 가능하며, 찬성과 반대를 각각 하나씩 내는 것도 가능하다. 또, 반드시 두 표를 내야 한다.

다음 라운드에 진출하는 참가자의 수는 정해져 있지 않다. 즉, 실력이 참가자의 경연이 모두 나쁜 경우에는 다음 라운드에 진출하는 참가자가 없을 수도 있고, 모두 엄청난 경연을 한 경우에는 모든 참가자기 다음 라운드에 진출할 수도 있다.

상근이는 심판들이 자신의 프로그래밍 능력에 큰 관심을 보이지 않을 것 같아 걱정하고 있다. 따라서, 상근이는 해킹을 이용해서 다음 라운드에 진출하려고 한다. 상근이는 투표 집계 시스템을 해킹해서, 다음 라운드 진출자를 선택하는 프로그램을 바꿔치기 하려고 한다. 하지만, 의심을 받지 않아야 한다.

각 심사위원은 자신이 행사한 두 표 중 적어도 하나는 결과에 영향을 미쳐야 한다고 생각을 한다. 두 표 모두와 반대되는 결과가 나오면, 심사위원은 투표 결과에 대해서 의심을 하게 된다. 예를 들어, 고원섭 심사위원이 박현수 참가자에게 찬성을, 김선영 참가자에게 반대를 한 경우를 생각해보자. 이 경우에 김선영이 다음 라운드에 진출하고, 박현수가 탈락을 하게 된다면, 두 결과가 모두 영향을 미치지 못했기 때문에, 고원섭 심사위원은 투표를 의심하게 된다.

상근이는 심사위원의 의심을 받지 않으면서, 다음 라운드에 진출하는 목록을 만들 수 있는지를 알고 싶어 한다. 당연히 이 목록에는 상근이가 포함되어 있어야 한다. 각 심사위원이 투표한 결과가 주어졌을 때, 상근이가 포함된 다음 라운드 진출 목록을 만들 수 있는지 없는지를 구하는 프로그램을 작성하시오.

입력

입력은 여러 개의 테스트 케이스로 이루어져 있다.

각 테스트 케이스의 첫째 줄에는 참가자의 수 n (2 ≤ n < 1000) 과 심사위원의 수 m (1 ≤ m < 2000)이 주어진다.

다음 m개 줄에는 각 심사위원이 행사한 투표의 정보 a와 b가 주어진다. (1 ≤ |a|, |b| ≤ n, |a| ≠ |b|) 정보가 x < 0인 경우에는 그 심사위원이 참가자 |x|에게 반대표를 행사한 것이고, x > 0인 경우는 |x|에게 찬성을 던진 것이다.

참가자의 번호는 1번부터 n번이다. 상근이는 1번 참가자이다. 

출력

각 테스트 케이스에 대해서, 상근이를 포함해, 다음 라운드 진출 목록을 심사위원의 의심 없이 만들 수 있으면 'yes'를, 없으면 'no'를 출력한다.

예제 입력 1

4 3
1 2
-2 -3
2 4
2 4
1 2
1 -2
-1 2
-1 -2

예제 출력 1

yes
no
[{"problem_id":"3648","problem_lang":"0","title":"\uc544\uc774\ub3cc","description":"<p>\uc0c1\uadfc\uc774\ub294 \uc624\ub514\uc158 \ud504\ub85c\uadf8\ub7a8 \ub300\ud55c\ubbfc\uad6d \uc544\uc774\ub3cc\uc758 \uc608\uc120\uc5d0 \ucc38\uac00\uc911\uc774\ub2e4.<\/p>\r\n\r\n<p>\ub300\ud55c\ubbfc\uad6d \uc544\uc774\ub3cc \uc624\ub514\uc158 \ud504\ub85c\uadf8\ub7a8\uc5d0\uc11c \ucc38\uac00\uc790\ub294 \uc2ec\uc0ac\uc704\uc6d0\uc5d0\uac8c 10\ubd84\ub3d9\uc548 \uc790\uc2e0\uc758 \ub9e4\ub825\uc744 \ubc1c\uc0b0\ud560 \uae30\ud68c\ub97c \uac16\ub294\ub2e4. \ubaa8\ub4e0 \ucc38\uac00\uc790\uac00 \uacbd\uc5f0\uc774 \ub05d\ub09c\ud6c4\uc5d0, \uc2ec\uc0ac\uc704\uc6d0\uc740 \ubaa8\ub450 \ubaa8\uc5ec\uc11c \ud22c\ud45c\ub97c \ud558\uac8c \ub41c\ub2e4. \uac01 \uc2ec\uc0ac\uc704\uc6d0\uc740 \ub2e4\uc74c \ub77c\uc6b4\ub4dc\uc5d0 \uaf2d \uc9c4\ucd9c\uc2dc\ucf30\uc73c\uba74 \ud558\ub294 \uc0ac\ub78c(\ucc2c\uc131)\uc774\ub098 \uc774\ubc88 \ub77c\uc6b4\ub4dc\uc5d0\uc11c \uaf2d \ud0c8\ub77d\uc2dc\ucf30\uc73c\uba74 \ud558\ub294 \uc0ac\ub78c(\ubc18\ub300)\uc744 \ub450 \uba85 \uace0\ub978\ub2e4. \ud55c \uc2ec\uc0ac\uc704\uc6d0\uc774 \ucc2c\uc131\ud45c\ub97c \ub450 \uac1c \ub0b4\ub294 \uac83\uacfc \ubc18\ub300\ud45c\ub97c \ub450 \uac1c \ub0b4\ub294 \uac83\ub3c4 \uac00\ub2a5\ud558\uba70, \ucc2c\uc131\uacfc \ubc18\ub300\ub97c \uac01\uac01 \ud558\ub098\uc529 \ub0b4\ub294 \uac83\ub3c4 \uac00\ub2a5\ud558\ub2e4. \ub610, \ubc18\ub4dc\uc2dc \ub450 \ud45c\ub97c \ub0b4\uc57c \ud55c\ub2e4.<\/p>\r\n\r\n<p>\ub2e4\uc74c \ub77c\uc6b4\ub4dc\uc5d0 \uc9c4\ucd9c\ud558\ub294 \ucc38\uac00\uc790\uc758 \uc218\ub294 \uc815\ud574\uc838 \uc788\uc9c0 \uc54a\ub2e4. \uc989, \uc2e4\ub825\uc774 \ucc38\uac00\uc790\uc758 \uacbd\uc5f0\uc774 \ubaa8\ub450 \ub098\uc05c \uacbd\uc6b0\uc5d0\ub294 \ub2e4\uc74c \ub77c\uc6b4\ub4dc\uc5d0 \uc9c4\ucd9c\ud558\ub294 \ucc38\uac00\uc790\uac00 \uc5c6\uc744 \uc218\ub3c4 \uc788\uace0, \ubaa8\ub450 \uc5c4\uccad\ub09c \uacbd\uc5f0\uc744 \ud55c \uacbd\uc6b0\uc5d0\ub294 \ubaa8\ub4e0 \ucc38\uac00\uc790\uae30 \ub2e4\uc74c \ub77c\uc6b4\ub4dc\uc5d0 \uc9c4\ucd9c\ud560 \uc218\ub3c4 \uc788\ub2e4.<\/p>\r\n\r\n<p>\uc0c1\uadfc\uc774\ub294 \uc2ec\ud310\ub4e4\uc774 \uc790\uc2e0\uc758 \ud504\ub85c\uadf8\ub798\ubc0d \ub2a5\ub825\uc5d0 \ud070 \uad00\uc2ec\uc744 \ubcf4\uc774\uc9c0 \uc54a\uc744 \uac83 \uac19\uc544 \uac71\uc815\ud558\uace0 \uc788\ub2e4. \ub530\ub77c\uc11c, \uc0c1\uadfc\uc774\ub294 \ud574\ud0b9\uc744 \uc774\uc6a9\ud574\uc11c \ub2e4\uc74c \ub77c\uc6b4\ub4dc\uc5d0 \uc9c4\ucd9c\ud558\ub824\uace0 \ud55c\ub2e4. \uc0c1\uadfc\uc774\ub294 \ud22c\ud45c \uc9d1\uacc4 \uc2dc\uc2a4\ud15c\uc744 \ud574\ud0b9\ud574\uc11c, \ub2e4\uc74c \ub77c\uc6b4\ub4dc \uc9c4\ucd9c\uc790\ub97c \uc120\ud0dd\ud558\ub294 \ud504\ub85c\uadf8\ub7a8\uc744 \ubc14\uafd4\uce58\uae30 \ud558\ub824\uace0 \ud55c\ub2e4. \ud558\uc9c0\ub9cc, \uc758\uc2ec\uc744 \ubc1b\uc9c0 \uc54a\uc544\uc57c \ud55c\ub2e4.<\/p>\r\n\r\n<p>\uac01 \uc2ec\uc0ac\uc704\uc6d0\uc740 \uc790\uc2e0\uc774 \ud589\uc0ac\ud55c \ub450 \ud45c \uc911 \uc801\uc5b4\ub3c4 \ud558\ub098\ub294 \uacb0\uacfc\uc5d0 \uc601\ud5a5\uc744 \ubbf8\uccd0\uc57c \ud55c\ub2e4\uace0 \uc0dd\uac01\uc744 \ud55c\ub2e4. \ub450 \ud45c \ubaa8\ub450\uc640 \ubc18\ub300\ub418\ub294 \uacb0\uacfc\uac00 \ub098\uc624\uba74, \uc2ec\uc0ac\uc704\uc6d0\uc740 \ud22c\ud45c \uacb0\uacfc\uc5d0 \ub300\ud574\uc11c \uc758\uc2ec\uc744 \ud558\uac8c \ub41c\ub2e4. \uc608\ub97c \ub4e4\uc5b4, \uace0\uc6d0\uc12d \uc2ec\uc0ac\uc704\uc6d0\uc774 \ubc15\ud604\uc218 \ucc38\uac00\uc790\uc5d0\uac8c \ucc2c\uc131\uc744, \uae40\uc120\uc601 \ucc38\uac00\uc790\uc5d0\uac8c \ubc18\ub300\ub97c \ud55c \uacbd\uc6b0\ub97c \uc0dd\uac01\ud574\ubcf4\uc790. \uc774 \uacbd\uc6b0\uc5d0 \uae40\uc120\uc601\uc774 \ub2e4\uc74c \ub77c\uc6b4\ub4dc\uc5d0 \uc9c4\ucd9c\ud558\uace0, \ubc15\ud604\uc218\uac00 \ud0c8\ub77d\uc744 \ud558\uac8c \ub41c\ub2e4\uba74, \ub450 \uacb0\uacfc\uac00 \ubaa8\ub450 \uc601\ud5a5\uc744 \ubbf8\uce58\uc9c0 \ubabb\ud588\uae30 \ub54c\ubb38\uc5d0, \uace0\uc6d0\uc12d \uc2ec\uc0ac\uc704\uc6d0\uc740 \ud22c\ud45c\ub97c \uc758\uc2ec\ud558\uac8c \ub41c\ub2e4.<\/p>\r\n\r\n<p>\uc0c1\uadfc\uc774\ub294 \uc2ec\uc0ac\uc704\uc6d0\uc758 \uc758\uc2ec\uc744 \ubc1b\uc9c0 \uc54a\uc73c\uba74\uc11c, \ub2e4\uc74c \ub77c\uc6b4\ub4dc\uc5d0 \uc9c4\ucd9c\ud558\ub294 \ubaa9\ub85d\uc744 \ub9cc\ub4e4 \uc218 \uc788\ub294\uc9c0\ub97c \uc54c\uace0 \uc2f6\uc5b4 \ud55c\ub2e4. \ub2f9\uc5f0\ud788 \uc774 \ubaa9\ub85d\uc5d0\ub294 \uc0c1\uadfc\uc774\uac00 \ud3ec\ud568\ub418\uc5b4 \uc788\uc5b4\uc57c \ud55c\ub2e4. \uac01 \uc2ec\uc0ac\uc704\uc6d0\uc774 \ud22c\ud45c\ud55c \uacb0\uacfc\uac00 \uc8fc\uc5b4\uc84c\uc744 \ub54c, \uc0c1\uadfc\uc774\uac00 \ud3ec\ud568\ub41c \ub2e4\uc74c \ub77c\uc6b4\ub4dc \uc9c4\ucd9c \ubaa9\ub85d\uc744 \ub9cc\ub4e4 \uc218 \uc788\ub294\uc9c0 \uc5c6\ub294\uc9c0\ub97c \uad6c\ud558\ub294 \ud504\ub85c\uadf8\ub7a8\uc744 \uc791\uc131\ud558\uc2dc\uc624.<\/p>\r\n","input":"<p>\uc785\ub825\uc740 \uc5ec\ub7ec \uac1c\uc758 \ud14c\uc2a4\ud2b8 \ucf00\uc774\uc2a4\ub85c \uc774\ub8e8\uc5b4\uc838 \uc788\ub2e4.<\/p>\r\n\r\n<p>\uac01 \ud14c\uc2a4\ud2b8 \ucf00\uc774\uc2a4\uc758 \uccab\uc9f8 \uc904\uc5d0\ub294 \ucc38\uac00\uc790\uc758 \uc218 n (2 &le; n &lt; 1000) \uacfc \uc2ec\uc0ac\uc704\uc6d0\uc758 \uc218 m (1 &le; m &lt; 2000)\uc774 \uc8fc\uc5b4\uc9c4\ub2e4.<\/p>\r\n\r\n<p>\ub2e4\uc74c m\uac1c \uc904\uc5d0\ub294 \uac01 \uc2ec\uc0ac\uc704\uc6d0\uc774 \ud589\uc0ac\ud55c \ud22c\ud45c\uc758 \uc815\ubcf4 a\uc640 b\uac00 \uc8fc\uc5b4\uc9c4\ub2e4. (1 &le; |a|, |b| &le; n, |a| &ne; |b|) \uc815\ubcf4\uac00 x &lt; 0\uc778 \uacbd\uc6b0\uc5d0\ub294 \uadf8 \uc2ec\uc0ac\uc704\uc6d0\uc774 \ucc38\uac00\uc790 |x|\uc5d0\uac8c \ubc18\ub300\ud45c\ub97c \ud589\uc0ac\ud55c \uac83\uc774\uace0, x &gt; 0\uc778 \uacbd\uc6b0\ub294 |x|\uc5d0\uac8c \ucc2c\uc131\uc744 \ub358\uc9c4 \uac83\uc774\ub2e4.<\/p>\r\n\r\n<p>\ucc38\uac00\uc790\uc758 \ubc88\ud638\ub294 1\ubc88\ubd80\ud130 n\ubc88\uc774\ub2e4. \uc0c1\uadfc\uc774\ub294 1\ubc88 \ucc38\uac00\uc790\uc774\ub2e4.&nbsp;<\/p>\r\n","output":"<p>\uac01 \ud14c\uc2a4\ud2b8 \ucf00\uc774\uc2a4\uc5d0 \ub300\ud574\uc11c, \uc0c1\uadfc\uc774\ub97c \ud3ec\ud568\ud574, \ub2e4\uc74c \ub77c\uc6b4\ub4dc \uc9c4\ucd9c \ubaa9\ub85d\uc744 \uc2ec\uc0ac\uc704\uc6d0\uc758 \uc758\uc2ec \uc5c6\uc774 \ub9cc\ub4e4 \uc218 \uc788\uc73c\uba74 &#39;yes&#39;\ub97c, \uc5c6\uc73c\uba74 &#39;no&#39;\ub97c \ucd9c\ub825\ud55c\ub2e4.<\/p>\r\n","hint":"","original":"0","html_title":"0","problem_lang_tcode":"Korean"},{"problem_id":"3648","problem_lang":"1","title":"Idol","description":"<p>Karl is competing in the preliminary round of a talent show called North-Western European Idol (NWEI), and wants to advance to the next round: World Idol. In the talent show, each contestant gets 10 minutes to impress the judges. After all the contestants have performed, each of the judges will cast two distinct votes. A vote can be either in favour of a contestant (meaning this contestant should advance) or against a contestant (meaning this contestant should not advance). The number of contestants that advance to the next round is not known in advance; if there are only very bad contestants, then it is possible that nobody will advance, or if everybody is amazing, then everybody may advance.<\/p>\r\n\r\n<p>Karl is afraid that the judges will not appreciate his programming talents, and hence wants to use his other talent to advance to the next round: hacking. Having gained access to the jury system, Karl is capable of overriding the regular process of counting votes, and instead selecting exactly which contestants advance to the next round. The only problem is, he has to be careful not to arouse suspicion.<\/p>\r\n\r\n<p>Each judge expects that at least one of his (or her) own two votes corresponds to the outcome of the contest. If the outcome contradicts both votes, the judge becomes alarmed. As an example, assume judge Harry casts a vote in favour of Pete and a vote against Sally. If Sally advances and Pete does not, judge Harry will be alarmed and may discover Karl&rsquo;s tampering with the system.<\/p>\r\n\r\n<p>Since Karl&rsquo;s programming talents are limited (otherwise he would not have needed his hacking talents), he needs you to make a program that \ufb01nds out if there is a set of contestants, which includes himself, that he can select to advance to the next round by hacking the jury system, such that it does not alarm any of the judges.<\/p>\r\n","input":"<p>For each test case, the input is as follows:<\/p>\r\n\r\n<ul>\r\n\t<li>One line containing two positive integers: the number of contestants n (2 &le; n &lt; 1000) and the number of judges m (1 &le; m &lt; 2000).<\/li>\r\n\t<li>m lines containing the votes of each judge. Each of these line contains two integers: the numbers a (1 &le; |a| &le; n), and b (1 &le; |b| &le; n), the two votes of this judge (|a| &ne; |b|). A vote x &lt; 0 means that the vote is against advancement of contestant |x|. A vote x &gt; 0 means that the vote is in favour of contestant |x|.<\/li>\r\n<\/ul>\r\n\r\n<p>Contestants are numbered 1 ... n.<\/p>\r\n\r\n<p>Karl is contestant 1.<\/p>\r\n","output":"<p>For each test case, print one line of output containing the word &lsquo;yes&rsquo; if there is a set of contestants that advances to the next round that includes Karl, and does not alarm any of the judges. If there is no such set of contestants, the line should contain &lsquo;no&rsquo;.<\/p>\r\n","hint":"","original":"1","html_title":"0","problem_lang_tcode":"English"}]

출처

ICPC > Regionals > Europe > Northwestern European Regional Contest > NWERC 2012 I번