Wednesday, May 18, 2016

HackerRank Training DS 5

Parentheses Matching Check using stack .

Be careful ans = true only when no mismatch occured and stack was "EMPTY" . else ans = No.


Try to avoid STL stack .It has many limitations .Try to use vector to imitate stack or use plain array (Best to avoid some SegFault error).



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/****************************************

@_@
Cat Got Bored *_*
#_#
*****************************************/

#include <bits/stdc++.h>


#define loop(i,s,e) for(int i = s;i<=e;i++) //including end point

#define pb(a) push_back(a)

#define sqr(x) ((x)*(x))

#define CIN ios_base::sync_with_stdio(0); cin.tie(0);

#define ll long long

#define ull unsigned long long

#define SZ(a) int(a.size())

#define read() freopen("input.txt", "r", stdin)

#define write() freopen("output.txt", "w", stdout)


#define ms(a,b) memset(a, b, sizeof(a))

#define all(v) v.begin(), v.end()

#define PI acos(-1.0)

#define pf printf

#define sfi(a) scanf("%d",&a);

#define sfii(a,b) scanf("%d %d",&a,&b);

#define sfl(a) scanf("%lld",&a);

#define sfll(a,b) scanf("%lld %lld",&a,&b);

#define mp make_pair

#define paii pair<int, int>

#define padd pair<dd, dd>

#define pall pair<ll, ll>

#define fs first

#define sc second

#define CASE(t) printf("Case %d: ",++t) // t initialized 0

#define INF 1000000000   //10e9

#define EPS 1e-9


using namespace std;
char paren[1009];
char validator[1009];
int main()
{
    //write();

    int T;
    cin>>T;
    loop(t,1,T)
    {
        int idx = 0;


        scanf("%s",paren);

        int ans = 1;
        loop(x,0,strlen(paren)-1)
        {


            char curBrace = paren[x];
            if(curBrace=='(' || curBrace=='{' || curBrace=='[')
                validator[idx++]=(curBrace);

            else if(curBrace==')')
            {
                char cB = validator[idx-1];
                if(cB!='(')
                {
                    ans = 0;
                    break;
                }
                idx--;
            }
            else if(curBrace=='}')
            {
                char cB = validator[idx-1];
                if(cB!='{')
                {
                    ans = 0;
                    break;
                }
                idx--;
            }

            else if(curBrace==']')
            {
                char cB = validator[idx-1];
                if(cB!='[')
                {
                    ans = 0;
                    break;
                }
                idx--;
            }


        }

        if(ans && idx==0) //idx==0 is very important 
        //what if the test input is {((([ After checking there will be no mismatch but still ans = No as "STACK NOT EMPTY"
            pf("YES\n");
        else
            pf("NO\n");
        //paren.clear();
        //validator.clear();



    }



    return 0;
}

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