Codeforces A. Summer Camp 672A Codeforces Round #352 (Div. 2)

Problem link


This problem says just print input position value.
First, you need to store the value in an array then you print this, but this series is 123456789101112131415...so if the input is 9 so our answer is 9, if the input is 10 then our output is 1 if our input is 11 so answer is 0... soon.

so how to way we can solve this problem. 

The first way we can store 1 to 1000 num in a string or character array then just print this position number value.

The second way is a very nice way to solve this problem, we can use a loop 1 to 1000 and we can call a function within the loop. this function work is found all last number in a number, Example our num is 123 so our last number is 3 then 2 and then 1. so we can use a vector/ array and save this all last numbers in one number. then we can reverse this so now our reverse last number is 1, 2 and 3. we can use this logic in 1 to 1000 number(with loop you can see simple code).
then just print array index number value and it's our problem expected answer.



A solution in c++

#include<bits/stdc++.h>

using namespace std;

/// Typedef
typedef long long ll;

#define sc1(a) scanf("%lld",&a)
#define sc2(a,b) scanf("%lld %lld",&a,&b)

#define pf1(a) printf("%lld\n",a)
#define pf2(a,b) printf("%lld %lld\n",a,b)

#define mx 1000010
#define mod 10000007
#define PI acos(-1.0)

vector<ll>vc;

ll check(ll n)
{
    ll size1 = vc.size();
    while (n!=0){
        vc.push_back(n % 10);
        n /= 10;
    }
    ll size2 = vc.size();
    reverse(vc.begin()+size1, vc.begin()+size2);
}

int main()
{
    ll row, col, tc, t = 1;

    sc1(tc);

    for(ll i = 1; i <= tc; i++){
        check(i);
    }

   cout << vc[tc - 1] << endl;

}



OR


#include <iostream>
#include <string>
using namespace std;
int n;
string a;
int main() {
    cin >> n;
    for (int i = 1; i <= n; i++) {
        a += to_string(i);
    }
    cout << a[n - 1];

}



OR


#include<bits/stdc++.h>

using namespace std;

int n,i;
char arr[3000] = "1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253545556575859606162636465666768697071727374757677787980818283848586878889909192939495969798991001011021031041051061071081091101111121131141151161171181191201211221231241251261271281291301311321331341351361371381391401411421431441451461471481491501511521531541551561571581591601611621631641651661671681691701711721731741751761771781791801811821831841851861871881891901911921931941951961971981992002012022032042052062072082092102112122132142152162172182192202212222232242252262272282292302312322332342352362372382392402412422432442452462472482492502512522532542552562572582592602612622632642652662672682692702712722732742752762772782792802812822832842852862872882892902912922932942952962972982993003013023033043053063073083093103113123133143153163173183193203213223233243253263273283293303313323333343353363373383393403413423433443453463473483493503513523533543553563573583593603613623633643653663673683693703713723733743753763773783793803813823833843853863873883893903913923933943953963973983994004014024034044054064074084094104114124134144154164174184194204214224234244254264274284294304314324334344354364374384394404414424434444454464474484494504514524534544554564574584594604614624634644654664674684694704714724734744754764774784794804814824834844854864874884894904914924934944954964974984995005015025035045055065075085095105115125135145155165175185195205215225235245255265275285295305315325335345355365375385395405415425435445455465475485495505515525535545555565575585595605615625635645655665675685695705715725735745755765775785795805815825835845855865875885895905915925935945955965975985996006016026036046056066076086096106116126136146156166176186196206216226236246256266276286296306316326336346356366376386396406416426436446456466476486496506516526536546556566576586596606616626636646656666676686696706716726736746756766776786796806816826836846856866876886896906916926936946956966976986997007017027037047057067077087097107117127137147157167177187197207217227237247257267277287297307317327337347357367377387397407417427437447457467477487497507517527537547557567577587597607617627637647657667677687697707717727737747757767777787797807817827837847857867877887897907917927937947957967977987998008018028038048058068078088098108118128138148158168178188198208218228238248258268278288298308318328338348358368378388398408418428438448458468478488498508518528538548558568578588598608618628638648658668678688698708718728738748758768778788798808818828838848858868878888898908918928938948958968978988999009019029039049059069079089099109119129139149159169179189199209219229239249259269279289299309319329339349359369379389399409419429439449459469479489499509519529539549559569579589599609619629639649659669679689699709719729739749759769779789799809819829839849859869879889899909919929939949959969979989991000";

int main()
{

    cin>>n;
    cout<<arr[n-1]<<endl;

}