Problem: Cellphone Typing

link: UVA 12526

Problem:
             We have to say average number of keystroke, we have to press while typing given words of dictionary.

Idea:
       1.) Just store given words of dictionary in a trie.
       2.) Then, for all of these words count , how many keystroke needed to type., at last avrg the sum.

Solution:
         
/************************************************************
 *                                                          *
 *            ==>>BG_PeaceMind(BISHAL)               @NEPAL *
 *************************************************************/
 ///AC- rank-81
#include <bits/stdc++.h>
#define PI acos(-1.0)
#define M 100005
#define S(a) scanf("%d",&a)
#define P(a) printf("%d\n",a)
#define S2(a,b) scanf("%d%d",&a,&b)
#define clr(a) memset(a,0,sizeof(a))
#define SET(a) memset(a,-1,sizeof(a))
#define ff(a) memset(a,false,sizeof(a))
#define pb(x) push_back(x)
#define fs first
#define sc second
#define mpr(x,y) make_pair(x,y)
#define all(v) v.begin(),v.end()
#define fr(i,a,n) for(i=a;i<=n;i++)
using namespace std;
typedef long long ll;
struct trie
{
    int cnt,dis_cnt,len,next[27];
    bool isend;
    trie()
    {
        cnt=len=isend=dis_cnt=0;
        SET(next);
    }
};
trie T[M*15];
int tot;
void Ins(char *s)
{
    int p=0;
    T[p].cnt++;
    for(int i=0;s[i];i++)
    {
        int k=s[i]-'a';
        if(T[p].next[k]==-1)
        {
            T[p].next[k]=++tot;
            T[tot]=trie();
        }
        p=T[p].next[k];
        T[p].cnt++;
        T[p].len=i+1;
    }
    T[p].isend=true;
    T[p].dis_cnt++;
}
int countStroke( char *s)
{
    int p=0,prev=0,cnt=0;
    for(int i=0;s[i];i++)
    {
        int k=s[i]-'a';
        if(i==0)
        {
            cnt++;
            prev=T[p].next[k];
            p=T[p].next[k];
            continue;
        }
        p=T[p].next[k];
       // if(p==-1)break;
        if(T[prev].cnt!=T[p].cnt)cnt++;
        prev=p;
    }
    return cnt;
}
char s[M][100];
int main()
{
    int n,m,i,j,k;
    while(S(n)==1)
    {
      //  clr(T);
        tot=0;
        T[0]=trie();
        getchar();
        fr(i,1,n)
        {
            gets(s[i]);
            Ins(s[i]);
        }
        ll ct=0,sm=0;
        fr(i,1,n)
        {
            ct=countStroke(s[i]);
          //  cout<<ct<<endl;
            sm+=ct;
        }
       // cout<<sm<<endl;
        printf("%.2lf\n",(sm*1.0/(n*1.0)) );
    }
    return 0;
}

 

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