Problema 23

Sa se genereze n perechi de paranteze care se inchid corect. Exemplu: n=3: ( ( ( ) ) ) ( ( ) ( ) ) ( ) ( ( ) ) etc

#include<iostream.h>

int x[100],n,t;

void afisare()

{int j;

cout<<endl;

for(j=1;j<=2*n;j++)

if(x[j]==1)

cout<<"(";

else

cout<<")";

}

int cont(int k)

{ int i; pi=0;pd=0;

for(i=1;i<=k;i++)

if(x[i]==1)

pd++;

else

pi++;

if(pi>pd)

return 0;

if(x[1]==2 && k==1)

return 0;

if(k==2*n && pi!=pd)

return 0;

return1;}

void back(int k)

{int i;

for(i=1;i<=2;i++)

{x[k]=i;

if(cont(k))

if(k==2*n)

afisare();

else

back(k+1);}}

int main()

{cin>>n;

back(1);}