AtCoder Beginner Contest 161

A

#include <bits/stdc++.h>
using namespace std;

int a,b,c;

signed main() {
    cin>>a>>b>>c;
    swap(a,b);
    swap(a,c);
    cout<<a<<" "<<b<<" "<<c<<endl;
}

B

#include <bits/stdc++.h>
using namespace std;

#define int long long
const int N = 1005;

int n,m,a[N],s;

signed main() {
    cin>>n>>m;
    for(int i=1;i<=n;i++) cin>>a[i], s+=a[i];
    int c=0;
    for(int i=1;i<=n;i++) if(a[i]*4*m>=s) ++c;
    cout<<(c>=m?"Yes":"No");
}

C

#include <bits/stdc++.h>
using namespace std;

#define int long long
int n,k;

signed main() {
    cin>>n>>k;
    if(n>k) n-=k*((n/k)-1);
    while(abs(n-k)<n) n=abs(n-k);
    cout<<n;
}

D
分段打表

#include <bits/stdc++.h>
using namespace std;

#define int long long

int a[5005]={0,4445,21122,45434,76667,110111,221122,323234,432332,456556,565566,667655,776767,887765,1001012,1122111,1232232,2122234,2233211,2334544,3223212,3332332,3434343,4321222,4345456,4454545,4556555,5443345,5545433,5654444,5677899,6565565,6667654,6776766,7665434,7766767,7877666,8767676,8877789,8998887,9987676,10101001,11010111,11123221,11233334,12123344,12234321,12343432,21110101,21221112,22111101,22222100,22323433,23211223,23321212,23345454,23454543,32122323,32233222,32334555,33223223,33332343,33434432,34321233,34345545,34454556,34556566,43222321,43332211,43433444,44321101,44344565,44454432,44555656,45443232,45544456,45654323,45677778,54343323,54444556,54554344,55433434,55543222,55566676,55676544,56555654,56665443,56766776,65433232,65456678,65566544,65667777,66555444,66656677,66766566,67654543,67678777,67788766,67899987,76566565,76667876,76777766,77665656,77767767,77877888,78767898,78878876,78999987,87677677,87787666,87898788,88787789,88898998,89887778,98765666,98876565,98988876,99898776,100012110,101000100,101121210,101232110,110101210,111011110,111123343,111233456,112210001,112234443,112344332,121111100,121221234,122111223,122222222,122332112,123212210,123322121,123345654,123455443,210111100,211012222,211211010,211234567,212211212,212321123,212345443,221112212,221223210,222112343,222223333,222333223,223221112,223323232,223432322,223456554,232210100,232234455,232344344,233232321,233334432,233443443,234323323,234432343,234456567,234565655,321110111,321221122,322111111,322222110,322323443,323211233,323321222,323345456,323454545,332122333,332233232,332334565,333223233,333332345,333434434,334322100,334345555,334454566,334556654,343222323,343332221,343433454,344321111,344344567,344454434,344555666,345443234,345544544,345654333,345677788,432123454,432234345,432343456,433232211,433334322,433443333,434323221,434432233,434456543,434565545,443223444,443333334,443434567,444322233,444432101,444455555,444556787,445444433,445545665,445655454,445678989,454344454,454454321,454555545,455434565,455544345,455567877,455677667,456556777,456666566,456767899,543221010,543322345,543432221,543455667,544343334,544444567,544554433,545433445,545543233,545566765,545676555,554334322,554443333,554544565,555432211,555455665,555565445,555666678,556554345,556655656,556765545,556789987,565455455,565556765,565666554,566545665,566655454,566678989,566788899,567676767,567778887,567889898,654343221,654444454,654545678,655433332,655456778,655566566,655667877,656555544,656656777,656766666,665432344,665456654,665565656,665667667,666554556,666656567,666765678,667654433,667677888,667787877,667899876,676565677,676667766,676777656,677665554,677767665,677877778,678767788,678878766,678999876,765454567,765556655,765665666,766545555,766654566,766678878,766788789,767676665,767778777,767888998,776556676,776666543,776767876,777656545,777765656,777876555,778766565,778876678,778988998,787667787,787777677,787887889,788777878,788888877,789877789,789998887,876565565,876667654,876776766,877665434,877766767,877877666,878767676,878877789,878998887,887676677,887778789,887889878,888778999,888898767,889878988,898765444,898789877,898987789,899888998,987656543,987765654,987876545,988766555,988876676,988988988,989898887,998776544,998878887,998999998,999988766,1000110000,1001011221,1001123454,1001234345,1010112233,1011101100,1011212222,1012101223,1012212345,1012322334,1100000111,1100121221,1101110121,1101221210,1110011121,1110123432,1111112345,1111223343,1112121123,1112232101,1112333434,1121012233,1121211100,1122100010,1122211223,1122321212,1122345454,1123233345,1123343234,1123444545,1210012233,1211001100,1211122112,1211232233,1212122321,1212233212,1212334545,1221101011,1221212212,1222101221,1222212343,1222322332,1223210101,1223234456,1223344345,1223445656,1232121221,1232232121,1232333454,1233222122,1233323455,1233433323,1233456777,1234344444,1234445677,1234555543,2100012121,2101000111,2101121221,2101232121,2110101221,2111011121,2111123432,2111234323,2112210012,2112234454,2112344343,2121111111,2121222110,2122111234,2122222233,2122332123,2123212221,2123322210,2123345665,2123455454,2210111111,2211012233,2211211100,2212100010,2212211223,2212321212,2212345454,2221112223,2221223221,2222121000,2222223344,2222333234,2223221123,2223323321,2223432333,2223456565,2232210111,2232234544,2232344433,2233232332,2233334443,2233443454,2234323334,2234433210,2234456656,2234565666,2321110122,2321221211,2322111122,2322222121,2322323454,2323212101,2323321233,2323345545,2323454556,2332122344,2332233321,2332343210,2333223322,2333333212,2333434445,2334322111,2334345566,2334455433,2334556665,2343222334,2343332232,2343434321,2344321122,2344345434,2344454445,2344555677,2345443323,2345544555,2345654344,2345677877,3210112121,3211100111,3211212110,3212101111,3212212233,3212322222,3212345677,3221121101,3221223444,3222121232,3222232210,3222334321,3223222211,3223332101,3223433334,3223456788,3232211211,3232321122,3232345434,3233233333,3233343222,3233444455,3234332122,3234433433,3234543221,3234566667};
int b[1445]={12345678,21000000,23456789,32100000,34567899,43210000,45678999,54321000,56789999,65432100,67899999,76543210,78999999,87654321,89999999,98765432,101234567,110000000,112345678,121000000,123456789,210000000,212345678,221000000,223456789,232100000,234567899,321000000,323456789,332100000,334567899,343210000,345678999,432100000,434567899,443210000,445678999,454321000,456789999,543210000,545678999,554321000,556789999,565432100,567899999,654321000,656789999,665432100,667899999,676543210,678999999,765432100,767899999,776543210,778999999,787654321,789999999,876543210,878999999,887654321,889999999,898765432,899999999,987654321,989999999,998765432,1001234567,1010000000,1012345678,1100000000,1101234567,1110000000,1112345678,1121000000,1123456789,1210000000,1212345678,1221000000,1223456789,1232100000,1234567899,2100000000,2101234567,2110000000,2112345678,2121000000,2123456789,2210000000,2212345678,2221000000,2223456789,2232100000,2234567899,2321000000,2323456789,2332100000,2334567899,2343210000,2345678999,3210000000,3212345678,3221000000,3223456789,3232100000};

map<int,int> mb;

int check(int x) {
    int last=x%10; x/=10;
    while(x) {
        int p=x%10; x/=10;
        if(abs(last-p)>1) return 0;
        last=p;
    }
    return 1;
}

//2100000000,3210000000,

signed main() {
    int ind=0;
    int n,p;
    cin>>n;
    p=n/200;
    int cnt=0;
    for(int i=0;i<=1000;i+=2) mb[b[i]]=b[i+1];
    for(int i=a[p];;i++) {
        if(check(i)) {
            if(cnt==n%200) {
                cout<<i;
                return 0;
            }
            ++cnt;
        }
        if(mb[i]) i=mb[i]-2;
    }
}