2017 Multi-University Training Contest 1 solutions 1002 Balala Power!（贪心）

每个字符对答案的贡献都可以看作一个 26 进制的数字，问题相当于要给这些贡献加一个 0 到 25 的权重使得答案最大。最大的数匹配 25，次大的数匹配 24，依次类推。排序后这样依次贪心即可，唯一注意的是不能出现前导 0。

#include <cstdio>#include <iostream>#include <algorithm>#include <cstdlib>using namespace std;struct me{    long long  type_size;    int type_num;}my[30];const int mmax=1e9+7;int comp(struct me a,struct me b){    return a.type_size>b.type_size;}int main(){    //freopen("/Users/wenhanmac/Desktop/1002.in", "r", stdin);    //freopen("/Users/wenhanmac/Desktop/1002.txt", "w", stdout);    int n;    int mycase=1;    while (cin>>n) {        char s[1000000];        for (int i=0; i<26; i++) {            my[i].type_num=i;            my[i].type_size=0;        }        int title[30]={0};        while (n--) {            scanf("%s",s);            int t=(int)strlen(s);            long long x=1;            for(int i=t-1;i>=0;i--)            {                my[s[i]-'a'].type_size+=x;                x=(x*26)%mmax;            }            title[s[0]-'a']++;            //printf("%d\n",mycase++);        }      for(int i=0;i<26;i++)            my[i].type_size%=mmax;           long long msum=0;        sort(my, my+26, comp);        if(my[25].type_size==0)        {            int num=25;            for (int i=0; i<26; i++) {                msum+=my[i].type_size*num;                num--;            }        }        else        {            int k=0;            for(int i=25;i>=0;i--)                if(title[my[i].type_num]==0)                {                    k=i;                    break;                }            int num=25;            for (int i=0; i<26; i++)                if(i!=k)                {                    msum=(msum+my[i].type_size*num)%mmax;                    num--;                }        }        printf("Case #%d: %lld\n",mycase++,msum%mmax);    }    return 0;}

上面是当时wa的代码，因为我把数的幂次也直接进行了取余，后来想到了感觉当时很可笑，下面是网上大神的代码

#include <string>#include <iostream>#include <algorithm>using namespace std;const int MAXN = 1e5+7;const long long mod = 1e9+7;int n;struct node{    int id;    int num[MAXN];    bool operator < (const node &a)const    {        for(int j = 100000; j >= 0; --j)if(num[j] != a.num[j])return num[j] > a.num[j];        return 0;    }}p[30];string s[MAXN];long long num[30];long long k[MAXN];bool ha[30];int main(){    ios::sync_with_stdio(false);    k[0] = 1;    for(int i = 1 ; i <= 100000; ++i)k[i] = (k[i-1]*26)%mod;        int ca = 0;    while(cin>>n)    {        for(int i = 0; i < 26; ++i)        {            for(int j=0; j<=100000; j++)p[i].num[j]=0;            p[i].id = i;            ha[i] = 0;        }                for(int i = 0; i < n; ++i)        {            cin>>s[i];            int l = s[i].size();            if(l > 1)ha[s[i][0]-'a'] = 1;            for(int ii = l-1,j=0; ii >=0; --ii,++j)            {                int t = s[i][ii]-'a';                p[t].num[j]++;            }        }                for(int i = 0; i < 26; ++i)        {            for(int j = 0; j <= 100000; ++j)            {                p[i].num[j+1] += p[i].num[j]/26;                p[i].num[j]%=26;            }        }        sort(p,p+26);        for(int i = 25; i >= 0; --i)num[p[25-i].id] = i;        int t = 25;        while(ha[p[t].id]&&t)        {            swap(num[p[t].id],num[p[t-1].id]);            t--;        }        long long ans = 0;        for(int i = 0; i < n; ++i)        {            int l = s[i].size();            for(int j = 0; j < l; ++j)            {                ans = (ans+num[s[i][j] -'a']*k[l-1-j]%mod)%mod;            }        }        cout<<"Case #"<<++ca<<": "<<ans<<endl;    }    return 0;}

下面给一些测试数据

100
kprfpnzqaqgvfdxwtq
ceilpmszizfwbonxplc
pkpbcfsesgfbiqnipolefre
phjthqrzsphbnumgri
mwiztfuhqibgaxdvysyvgxls
pminykbyumepubrxuo
dbielzdobgqcjznjbex
kghywioxzbvxzfc
shcozmefwcrvyibjd
mhxdpccjodlgvkplrfdedp
zoprfeechwszhvcdooejlchcwcek
rdmowhsueavbrawmihzsn
rafbqeawdixznppfwieai
mpqzqtsvnvwjmgvhue
sssaxgmoywdgvwiouzuq
debijcqycftaftu
wtgxavemciuqmxenprpm
zrexshnvtesstwhytma
xbuzxpstpygfxphp
ckjdbfbximeeswyndfhomc
wjtfruvzwbhlzbve
cepgcdpmghcibfxgrv
cxwlopxsvzclwymwdmoljta
wuvhxifdjqshlqaueglq
rbxuwpozfvegdpvnwmedxbmxa
mxmxgjlnnf
kwbrqshxfcanwpoflqe
jafdktnlpgvlexcyglr
zbkhcmxvuobyxcxzxqmlsw
mbvcsdtefcqtmlilwzt
scfhjtcytonmliivrkbblvnmh
prgeryrpjpjykchne
miefymajrnwjslytbxmd
wtfzafkxyfmcnljsebzley
jmkyylfmmv
jwgcyhrdldkzfzgtvm
wlbeqtjsodvhbuumexp
pcdxqhceqldfavgqlvituzzn
jeotbkjzcrtggluiamn
corbkiwdozitqgqiphvwuijwhs
mgogxomluqurcwogghh
jjcekggllamqgxhcfcmrakgrojgxizwxa
scasinzxcdxewculo
xhzxmjdlisupdylsha
cipzoptullyisxs
czjqawagnngcggiwkhnar
jisvcdpzggtlludvcsjxeu
jdimtpftgytkfntylnflb
syovxmligoaiqzlxwfrsljucdxs
samgcifdljashcjjwh
kqnipxzjglptedzxmthvzgru
ckufdecakrrzoqfqcduzhjsd
skqglqlnnbkuuytqthfcj
raawtbccur
pzpumcsmqhebhqrfi
mblzxycvevluzcuqxvrjgek
rvcohldavkjiykhccm
jpdhkkimpsmvcyqx
wlbhldkjlzwthkfnizebvlg
zrnwwvxdckgnckqtkqidhoociwrp
kxesldtgxtaurglbgmpyqlpzbnsbz
puziqurwrbrbxmhbrdpd
rerbobajuldlwrpkrtfblspn
kxyitiohlpgjlcktlaqsalnoiphb
rrghseznkmzukaiihatztti
ctadtninwcsufbynjk
xaajnagfevscfuhoaj
misgbbsxqbylm
raszacpliuglqyuzbnizxxj
xnntsckjzjzjmmyfmvxjaop
whbyoapkqedyddtrpblporu
rsknpbtamzkkzrrddcmrayg
juikqynjaucaqekhcwxd
pdohycvaexjyulgvw
sfivkvunqdekhngxjy
cspvzulhkywgqjgaq
clpsxnserdnrjxrozmxtjtv
ssyqpvotkhmbqaxi
xuxzlztksohujrt
mpdesfqjbjifgybebn
cfjteqfvsyrwwjzissaimg
cusleiacqxjipdt
jqrbldlirsiewjpln
dvvixjqtqjdozldbb
mvmveqlhjztcou
stcgromekrinqbgvgl
jhveaonqkrtjjtlgbkrnyo
xirslfszfqivgk
kctvbvksipwomqxlyqx
ceuhbjbfnhofcgpgwd
seffycthmlpcqejgsk
wjkbkbbmifnurnwyhevsoqz
mtvzgfiqajfrgyuzxnrt
xectcnlyoisbglpdbjbslxlp
mrcxmdtqhcnlvtqdwftuz
dxsyscwbrguostbelnvtaq
dmkmihmoxqtqlxvlsssisvqvvzo
ryuyqwoknnqcqggysrqpk
rccvyhxsjmhoqoyo
cwcriplarjoyiqrmmpmueqbs

100
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Case #1: 593296223

Case #2: 3124