{"id":46,"date":"2022-06-04T10:52:00","date_gmt":"2022-06-04T02:52:00","guid":{"rendered":"http:\/\/ubuntu.tim-wcx.ltd\/wordpress\/index.php\/2022\/06\/04\/2020-08-01\/"},"modified":"2022-06-04T10:52:00","modified_gmt":"2022-06-04T02:52:00","slug":"2020-08-01","status":"publish","type":"post","link":"https:\/\/wordpress.tim-wcx.ltd\/index.php\/2022\/06\/04\/2020-08-01\/","title":{"rendered":"2020-08-01"},"content":{"rendered":"

\n <\/path>\n <\/svg><\/p>\n

http:\/\/icpc.upc.edu.cn\/problem.php?cid=1459&pid=4<\/a><\/p>\n

<\/a>\u9898\u76ee\u63cf\u8ff0<\/h5>\n

Three friends like to play the following game. The first friend chooses a string S. Then the second friend constructs a new string T that consists of two copies of the string S. finally, the third friend inserts one letter at the beginning, the end or somewhere inside the string T, thereby creating a string U.
You are given the string U and your task is to reconstruct the original string S.<\/p>\n

<\/a>\u8f93\u5165<\/h5>\n

The first line of the input contains N\uff082 \u2264 N \u2264 2000001\uff09, the length of the final string U. The string U itself is given on the second line. It consists of N uppercase English letters (A, B, C, . . . , Z).<\/p>\n

<\/a>\u8f93\u51fa<\/h5>\n

Your program should print the original string S. However, there are two exceptions:
1.If the final string U could not have been created using the above procedure, you should print NOT POSSIBLE.
2.If the original string S is not unique, you should print NOT UNIQUE.<\/p>\n

<\/a>\u6837\u4f8b\u8f93\u5165<\/h5>\n
7\nABXCABC\n<\/code><\/pre>\n
<\/a>\u6837\u4f8b\u8f93\u51fa<\/h5>\n
ABC\n<\/code><\/pre>\n
<\/a>\u89e3\u6790<\/h5>\n
\u5b57\u7b26\u4e32\u54c8\u5e0c\u7684\u5e94\u7528\uff0c\u6bd4\u8f83\u53bb\u9664\u4e00\u4e2a\u5b57\u6bcd\u540e\u524d\u534a\u90e8\u5206\u7684\u54c8\u5e0c\u503c\u548c\u540e\u534a\u90e8\u5206\u54c8\u5e0c\u503c\u662f\u5426\u76f8\u540c<\/p>\n
#pragma<\/span> GCC optimize(1)<\/span>\n#pragma<\/span> GCC optimize(2)<\/span>\n#pragma<\/span> GCC optimize(3,\"Ofast\",\"inline\")<\/span>\n#include<\/span> <\/span><\/span>\nusing<\/span> namespace<\/span> std;<\/span>\ntypedef<\/span> long<\/span> long<\/span> ll;<\/span>\ntypedef<\/span> unsigned<\/span> long<\/span> long<\/span> ull;<\/span>\nconst<\/span> int<\/span> N=<\/span>2e6<\/span>+<\/span>500<\/span>;<\/span>\nchar<\/span> a[<\/span>N]<\/span>=<\/span>\"\"<\/span>;<\/span>\nint<\/span> base=<\/span>131<\/span>;<\/span>\null p[<\/span>N]<\/span>=<\/span>{<\/span>0<\/span>}<\/span>;<\/span>\null h[<\/span>N]<\/span>=<\/span>{<\/span>0<\/span>}<\/span>;<\/span>\null get<\/span>(<\/span>ull l,<\/span>ull r)<\/span>\n{<\/span>\n    return<\/span> h[<\/span>r]<\/span>-<\/span>h[<\/span>l-<\/span>1<\/span>]<\/span>*<\/span>p[<\/span>r-<\/span>l+<\/span>1<\/span>]<\/span>;<\/span>\n}<\/span>\nint<\/span> main<\/span>(<\/span>)<\/span>\n{<\/span>\n    int<\/span> n;<\/span>\n    scanf<\/span>(<\/span>\"%d\"<\/span>,<\/span>&<\/span>n)<\/span>;<\/span>\n    if<\/span>(<\/span>n%<\/span>2<\/span>==<\/span>0<\/span>)<\/span>\n    {<\/span>\n        printf<\/span>(<\/span>\"NOT POSSIBLEn\"<\/span>)<\/span>;<\/span>\n        return<\/span> 0<\/span>;<\/span>\n    }<\/span>\n    scanf<\/span>(<\/span>\"%s\"<\/span>,<\/span>a+<\/span>1<\/span>)<\/span>;<\/span>\n    p[<\/span>0<\/span>]<\/span>=<\/span>1<\/span>;<\/span>\n    for<\/span>(<\/span>int<\/span> i=<\/span>1<\/span>;<\/span>i<=<\/span>n;<\/span>i++<\/span>)<\/span>\n        p[<\/span>i]<\/span>=<\/span>p[<\/span>i-<\/span>1<\/span>]<\/span>*<\/span>base;<\/span>\n    for<\/span>(<\/span>int<\/span> i=<\/span>1<\/span>;<\/span>i<=<\/span>n;<\/span>i++<\/span>)<\/span>\n        h[<\/span>i]<\/span>=<\/span>h[<\/span>i-<\/span>1<\/span>]<\/span>*<\/span>base+<\/span>a[<\/span>i]<\/span>-<\/span>'A'<\/span>;<\/span>\n    ull flag=<\/span>0<\/span>,<\/span>ans,<\/span>pos;<\/span>    \/\/\/\u6ce8\u610f\u7528ull\uff0cans\u6570\u636e\u6bd4\u8f83\u5927<\/span>\n    for<\/span>(<\/span>int<\/span> i=<\/span>1<\/span>;<\/span>i<=<\/span>n;<\/span>i++<\/span>)<\/span>\n    {<\/span>\n        ull s1,<\/span>s2;<\/span>\n        if<\/span>(<\/span>i<=<\/span>n\/<\/span>2<\/span>)<\/span>\n        {<\/span>\n            s1=<\/span>h[<\/span>i-<\/span>1<\/span>]<\/span>*<\/span>p[<\/span>n\/<\/span>2<\/span>-<\/span>i+<\/span>1<\/span>]<\/span>+<\/span>get<\/span>(<\/span>i+<\/span>1<\/span>,<\/span>n\/<\/span>2<\/span>+<\/span>1<\/span>)<\/span>;<\/span>\n        }<\/span>\n        else<\/span>\n        {<\/span>\n            s1=<\/span>h[<\/span>n\/<\/span>2<\/span>]<\/span>;<\/span>\n        }<\/span>\n        if<\/span>(<\/span>i<=<\/span>n\/<\/span>2<\/span>+<\/span>1<\/span>)<\/span>\n        {<\/span>\n            s2=<\/span>get<\/span>(<\/span>n-<\/span>n\/<\/span>2<\/span>+<\/span>1<\/span>,<\/span>n)<\/span>;<\/span>\n        }<\/span>\n        else<\/span>\n        {<\/span>\n            s2=<\/span>get<\/span>(<\/span>n\/<\/span>2<\/span>+<\/span>1<\/span>,<\/span>i-<\/span>1<\/span>)<\/span>*<\/span>p[<\/span>n-<\/span>i]<\/span>+<\/span>get<\/span>(<\/span>i+<\/span>1<\/span>,<\/span>n)<\/span>;<\/span>\n        }<\/span>\n        if<\/span>(<\/span>s1==<\/span>s2)<\/span>\n        {<\/span>\n            if<\/span>(<\/span>flag&&<\/span>ans!=<\/span>s1)<\/span>\n            {<\/span>\n                printf<\/span>(<\/span>\"NOT UNIQUEn\"<\/span>)<\/span>;<\/span>\n                return<\/span> 0<\/span>;<\/span>\n            }<\/span>\n            ans=<\/span>s1;<\/span>\n            pos=<\/span>i;<\/span>\n            flag=<\/span>1<\/span>;<\/span>\n        }<\/span>\n    }<\/span>\n    if<\/span>(<\/span>flag)<\/span>\n    {<\/span>\n        for<\/span>(<\/span>int<\/span> i=<\/span>1<\/span>,<\/span>j=<\/span>0<\/span>;<\/span>j<<\/span>n\/<\/span>2<\/span>;<\/span>i++<\/span>)<\/span>\n        {<\/span>\n            if<\/span>(<\/span>i==<\/span>pos)<\/span>\n                continue<\/span>;<\/span>\n            else<\/span>\n                printf<\/span>(<\/span>\"%c\"<\/span>,<\/span>a[<\/span>i]<\/span>)<\/span>,<\/span>j++<\/span>;<\/span>\n        }<\/span>\n        printf<\/span>(<\/span>\"n\"<\/span>)<\/span>;<\/span>\n    }<\/span>\n    else<\/span>\n    {<\/span>\n        printf<\/span>(<\/span>\"NOT POSSIBLEn\"<\/span>)<\/span>;<\/span>\n    }<\/span>\n}<\/span>\n\n\n<\/code><\/pre>\n
<\/a>\u9898\u76ee\u63cf\u8ff0<\/h5>\n
\u4e00\u5757\u82b1\u5e03\u6761\uff0c\u91cc\u9762\u6709\u4e9b\u56fe\u6848\uff0c\u53e6\u6709\u4e00\u5757\u76f4\u63a5\u53ef\u7528\u7684\u5c0f\u9970\u6761\uff0c\u91cc\u9762\u4e5f\u6709\u4e00\u4e9b\u56fe\u6848\u3002\u5bf9\u4e8e\u7ed9\u5b9a\u7684\u82b1\u5e03\u6761\u548c\u5c0f\u9970\u6761\uff0c\u8ba1\u7b97\u4e00\u4e0b\u80fd\u4ece\u82b1\u5e03\u6761\u4e2d\u5c3d\u53ef\u80fd\u526a\u51fa\u51e0\u5757\u5c0f\u9970\u6761\u6765\u5462\uff1f<\/p>\n
<\/a>\u8f93\u5165<\/h5>\n
\u8f93\u5165\u4e2d\u542b\u6709\u4e00\u4e9b\u6570\u636e\uff0c\u5206\u522b\u662f\u6210\u5bf9\u51fa\u73b0\u7684\u82b1\u5e03\u6761\u548c\u5c0f\u9970\u6761\uff0c\u5176\u5e03\u6761\u90fd\u662f\u7528\u53ef\u89c1ASCII\u5b57\u7b26\u8868\u793a\u7684\uff0c\u53ef\u89c1\u7684ASCII\u5b57\u7b26\u6709\u591a\u5c11\u4e2a\uff0c\u5e03\u6761\u7684\u82b1\u7eb9\u4e5f\u6709\u591a\u5c11\u79cd\u82b1\u6837\u3002\u82b1\u7eb9\u6761\u548c\u5c0f\u9970\u6761\u4e0d\u4f1a\u8d85\u8fc71000\u4e2a\u5b57\u7b26\u957f\u3002\u5982\u679c\u9047\u89c1#\u5b57\u7b26\uff0c\u5219\u4e0d\u518d\u8fdb\u884c\u5de5\u4f5c\u3002<\/p>\n
<\/a>\u8f93\u51fa<\/h5>\n
\u8f93\u51fa\u80fd\u4ece\u82b1\u7eb9\u5e03\u4e2d\u526a\u51fa\u7684\u6700\u591a\u5c0f\u9970\u6761\u4e2a\u6570\uff0c\u5982\u679c\u4e00\u5757\u90fd\u6ca1\u6709\uff0c\u90a3\u5c31\u8001\u8001\u5b9e\u5b9e\u8f93\u51fa0\uff0c\u6bcf\u4e2a\u7ed3\u679c\u4e4b\u95f4\u5e94\u6362\u884c\u3002<\/p>\n
<\/a>\u6837\u4f8b\u8f93\u5165<\/h5>\n
abcde a3\naaaaaa  aa\n#\n<\/code><\/pre>\n
<\/a>\u6837\u4f8b\u8f93\u51fa<\/h5>\n
0\n3\n<\/code><\/pre>\n
<\/a>\u89e3\u6790<\/h5>\n
kmp\u6a21\u677f\u9898\u76ee\uff0c\u5339\u914d\u76f8\u540c\u7684\u5b57\u7b26\u4e32<\/p>\n
#include<\/span><\/span><\/span>\nusing<\/span> namespace<\/span> std;<\/span>\nchar<\/span> a[<\/span>2005<\/span>]<\/span>=<\/span>{<\/span>0<\/span>}<\/span>;<\/span>\nchar<\/span> str[<\/span>2005<\/span>]<\/span>=<\/span>{<\/span>0<\/span>}<\/span>;<\/span>\nint<\/span> Next[<\/span>2005<\/span>]<\/span>=<\/span>{<\/span>0<\/span>}<\/span>;<\/span>\nint<\/span> getNext<\/span>(<\/span>)<\/span>\n{<\/span>\n    int<\/span> i=<\/span>0<\/span>,<\/span>j=<\/span>-<\/span>1<\/span>;<\/span>\n    Next[<\/span>0<\/span>]<\/span>=<\/span>-<\/span>1<\/span>;<\/span>\n    while<\/span>(<\/span>a[<\/span>i]<\/span>)<\/span>\n    {<\/span>\n        if<\/span>(<\/span>j==<\/span>-<\/span>1<\/span>||<\/span>a[<\/span>i]<\/span>==<\/span>a[<\/span>j]<\/span>)<\/span>\n        {<\/span>\n            i++<\/span>;<\/span>\n            j++<\/span>;<\/span>\n            Next[<\/span>i]<\/span>=<\/span>j;<\/span>\n        }<\/span>\n        else<\/span>\n        {<\/span>\n            j=<\/span>Next[<\/span>j]<\/span>;<\/span>\n        }<\/span>\n    }<\/span>\n}<\/span>\nint<\/span> main<\/span>(<\/span>)<\/span>\n{<\/span>\n    while<\/span>(<\/span>1<\/span>)<\/span>\n    {<\/span>\n        scanf<\/span>(<\/span>\"%s\"<\/span>,<\/span>str)<\/span>;<\/span>\n        if<\/span>(<\/span>str[<\/span>0<\/span>]<\/span>==<\/span>'#'<\/span>)<\/span>\n            break<\/span>;<\/span>\n        memset<\/span>(<\/span>Next,<\/span>0<\/span>,<\/span>sizeof<\/span>(<\/span>Next)<\/span>)<\/span>;<\/span>\n        scanf<\/span>(<\/span>\"%s\"<\/span>,<\/span>a)<\/span>;<\/span>\n        getNext<\/span>(<\/span>)<\/span>;<\/span>\n        int<\/span> lena=<\/span>strlen<\/span>(<\/span>a)<\/span>,<\/span>lens=<\/span>strlen<\/span>(<\/span>str)<\/span>;<\/span>\n        int<\/span> j=<\/span>0<\/span>,<\/span>sum=<\/span>0<\/span>,<\/span>i=<\/span>0<\/span>;<\/span>\n        while<\/span>(<\/span>i<=<\/span>lens)<\/span>\n        {<\/span>\n            if<\/span>(<\/span>j==<\/span>-<\/span>1<\/span>||<\/span>str[<\/span>i]<\/span>==<\/span>a[<\/span>j]<\/span>)<\/span>\n            {<\/span>\n                i++<\/span>;<\/span>\n                j++<\/span>;<\/span>\n            }<\/span>\n            else<\/span>\n            {<\/span>\n                j=<\/span>Next[<\/span>j]<\/span>;<\/span>\n            }<\/span>\n            if<\/span>(<\/span>j==<\/span>lena)<\/span>\n            {<\/span>\n                sum++<\/span>;<\/span>\n                j=<\/span>0<\/span>;<\/span>\n            }<\/span>\n        }<\/span>\n        printf<\/span>(<\/span>\"%dn\"<\/span>,<\/span>sum)<\/span>;<\/span>\n    }<\/span>\n}<\/span>\n\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
http:\/\/icpc.upc.edu.cn\/pr…<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[1],"tags":[],"class_list":["post-46","post","type-post","status-publish","format-standard","hentry","category-uncategorized"],"_links":{"self":[{"href":"https:\/\/wordpress.tim-wcx.ltd\/index.php\/wp-json\/wp\/v2\/posts\/46","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/wordpress.tim-wcx.ltd\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/wordpress.tim-wcx.ltd\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/wordpress.tim-wcx.ltd\/index.php\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/wordpress.tim-wcx.ltd\/index.php\/wp-json\/wp\/v2\/comments?post=46"}],"version-history":[{"count":0,"href":"https:\/\/wordpress.tim-wcx.ltd\/index.php\/wp-json\/wp\/v2\/posts\/46\/revisions"}],"wp:attachment":[{"href":"https:\/\/wordpress.tim-wcx.ltd\/index.php\/wp-json\/wp\/v2\/media?parent=46"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/wordpress.tim-wcx.ltd\/index.php\/wp-json\/wp\/v2\/categories?post=46"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/wordpress.tim-wcx.ltd\/index.php\/wp-json\/wp\/v2\/tags?post=46"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
http:\/\/icpc.upc.edu.cn\/problem.php?cid=1459&pid=10<\/a><\/p>\n