Why is this code showing WA for https://www.codechef.com/LTIME81B/problems/POPGATES

general
1

#include<stdio.h>
#include<string.h>
int main()
{int te;
scanf("%d",&te);
while(te–){
long int n,k,i,t,h=0,cnt=0;
scanf("%ld",&n);
scanf("%ld",&k);
char str[n];
for(i=0;i<n;i++)
{
scanf(" %c", &str[i]);

}

for(i=n-k;i<n;i++)
{
   if(str[i]=='H')
   {
       cnt++;
   }
}
for(i=0;i<n-k;i++)
{
    if(str[i]=='H')
    {
        h++;
    }
}
t= n-k-h;
if(cnt%2==0)
{
    printf("%d\n", h);
}
else
{
    printf("%d\n",t);  
}}
return 0;

}

2

Consider the scenario [ … H H ] ,Here the first H is (n-k)th position. According to your logic, since 2 H’s are encountered from n-k th position the previous sequence wouldn’t be altered and you will print h heads, whereas the rightmost H would reverse the H prior to it and make it T while also reversing the entire sequence. Since now the n-k th position holds T the answer would be the no of heads in reversed sequence which is t Heads.
So you only need to check the character at n-k th position and if it is H print h else print t;
Modified your code : CodeChef: Practical coding for everyone

3

thank you very much i never thought about it !