429 - Word Transformation

[konsept]

I can't figure out why I get a WA with my solution.
the basic idea is to treat the words as a graph, with edges between 2 words iff they differ by exactly 1 letter. once we tranform it into graph form we can apply the FLoyd Warshall O( n^3 ) algorithm to find the best way of transorming any word to any other word.

[cpp]#include <stdio.h>
#include <string>
#include <vector>
#include <map>
#include <iostream>

using namespace std;

int cnt( string a, string b ){
if ( a.size() != b.size() ) return 0;
int x=0;
for ( int i=0; i<a.size(); i++ )
x+= (a!=b);
return x;
}

int dist[201][201];
map< string, int > ind;
vector<string> w;

int main( void ){
FILE *in=stdin;

int i,j,k,n;

n=0;
while ( 1 ){
string m;
char c[512];
fscanf( in, "%s", c );
m=c;
if ( m=="*" ) break;

ind[ m ]=n;
w.push_back( m );
dist[n][n]=0;

for ( i=0; i<n; i++ ){
k=cnt(w,w[n]);
if ( k==1 ){
dist[n]=dist[n]=1;
// printf( "linkF: %s %s\n", w.c_str(), w[n].c_str() );
}
else
dist[n]=dist[n]=10000001;
}

n++;
}

for ( k=0; k<n; k++ )
for ( i=0; i<n; i++ )
for ( j=0; j<n; j++ )
dist[j]=min( dist[j], dist[i][k]+dist[k][j] );

char a[512],b[512];

while ( 2==fscanf( in, "%s %s", a,b ) ){
string x=a; string y=b;
printf( "%s %s %d\n", a,b,dist[ ind[x] ][ ind[y] ] );
}

return 0;
}[/cpp]

[Stefan Pochmann]

Long live multiple input, for the joy of all of us!

[konsept]

the problem statement states that after the pairs of words there is a EOF
so how can you have multiple input??

assuming its possible to have multiple input how can you distinguish between the end of the pairs of words section and the start of a new data set?

you can answer this by modifying my code for me to handle multiple inputs, if you want

[Stefan Pochmann]

Read the description of multiple input format. There is a blank line between the inputs, that's how you know when to start all over again.

[konsept]

so now I have to worry about blank lines??
forget this problem.

[Stefan Pochmann]

Oh, come on... Just read the complete line with "gets" or "getline" and then use "sscanf" or an "istringstream" to check for empty line and to read the two words.

[Pupirev Sergei]

I can't understand why WA. I use usual Floyd algorithm
[cpp]#include <fstream.h>
#include <string.h>
#define max 201
//#define cin in
//ifstream in("input.txt");
int a[max][max];
int n;

void floyd()
{
int i,j,k;
for (i=0;i<n;i++)
for (j=0;j<n;j++)
for (k=0;k<n;k++)
if (a[j]>a[k]+a[k][j]) a[j]=a[k]+a[k][j];
}

char dic[max][11];
int kol=0;
int bs(char *s)
{
int i;
for (i=0;i<kol;i++)
if (strcmp(dic,s)==0) return i;
return -1;
}
int ok(char *s1,char *s2)
{
int r=0,i;
if (strlen(s1)!=strlen(s2)) return 0;
for (i=0;i<strlen(s1);i++)
if (s1!=s2) r++;
if (r==1) return 1;
return 0;
}
void read(char *s,char *s1,char *s2)
{
int i=0;
while (s>'z' || s<'a') i++;
int j=0;
while (s<='z' && s[i]>='a') {s1[j]=s[i];i++;j++;}
s1[j]=0;
while (s[i]>'z' || s[i]<'a') i++;
j=0;
while (i<strlen(s) && s[i]<='z' && s[i]>='a') {s2[j]=s[i];i++;j++;}
s2[j]=0;
}
int main()
{
int ntest,t;
cin>>ntest;
for (t=0;t<ntest;t++){
if (t!=0) cout<<"\n";
kol=0;n=0;
int i;
cin>>dic[kol];
while (dic[kol][0]!='*')
{
kol++;
cin>>dic[kol];
}
n=kol;
int j;
for (i=0;i<n;i++)
for (j=0;j<n;j++)
if (i!=j) a[i][j]=10000;
else a[i][j]=0;
for (i=0;i<n;i++)
for (j=i+1;j<n;j++)
if (ok(dic[i],dic[j])==1)
{
a[i][j]=1;
a[j][i]=1;
}

char s1[11],s2[11];
char s3[30];
cin.getline(s3,30);
cin.getline(s3,30);
floyd();
while (strlen(s3)!=0)
{
read(s3,s1,s2);
int k1=bs(s1);
int k2=bs(s2);
cout<<s1<<" "<<s2<<" "<<a[k1][k2]<<"\n";
cin.getline(s3,30);
}
}
return 0;
}[/cpp]

[the LA-Z-BOy]

your floyd algorithm is wrong here...the intermediate node selection loop (k=0; k<... in your code) should be the outer most loop and also you are not creating new paths where direct edge is not possible.
so modifying a little your floyd algo should be ok[cpp]void floyd()
{
int i,j,k;
for (k=0;k<n;k++)
for (i=0;i<n;i++)
for (j=0;j<n;j++)
if (a[j]==0 || a[j]>a[k]+a[k][j])
a[j]=a[k]+a[k][j];
}
[/cpp]
greetings

[Pupirev Sergei]

Thanks, a lot!
It is so funny bug!
But i should not write if (a[j]==0 || ...) as first i have a[j]=10000 (infinity).

[the LA-Z-BOy]

oh sorry, i missed that.

[Junayeed]

I try to solve this problem. But i am getting RTE.
Please help me with some multiple inputs.

Thanks.

[juli3079fe]

Hello guys,
I sent the following code and i got WA, is there anyone has any idea why?
[cpp]
#include <cstdio>
#include <vector>
#include <iostream>
#include <string>
#include <cstring>
#include <queue>
using namespace std;

typedef struct{
char words[11];
bool visited;
int dist;
vector<int> neigh;
}Word;

typedef struct{
Word wlist[10][200];
int size[10];
}WList;


int search_path(WList *wl, int len, int spos, int tpos){
int pos;
int count;
int path = 1;
vector<int>::iterator en;
vector<int>::iterator bg;
bool found = false;
queue<int> q;
q.push(spos);

for(int i=0;i<200;i++) wl->wlist[len].visited = false;

wl->wlist[len][spos].visited = true;
wl->wlist[len][spos].dist = 0;
while(!q.empty()){
pos = q.front();
q.pop();
en = wl->wlist[len][pos].neigh.end();
bg = wl->wlist[len][pos].neigh.begin();
for(vector<int>::iterator it=bg;it!=en;it++){
if(!wl->wlist[len][*it].visited){
path=wl->wlist[len][*it].dist = wl->wlist[len][pos].dist+1;
count = 0;
for(int i=0;i<=len;i++){
if(wl->wlist[len][tpos].words == wl->wlist[len][*it].words) count++;
}

if( count == (len+1) ) {
found = true;
goto outerloop;
}
q.push(*it);
wl->wlist[len][*it].visited = true;
}
}
}

outerloop:
if(found) return path;
return 0;
}

int main(int argc,char **argv){

char input[50];
char temp[50];
WList dict;
size_t len;
string output = "";
char *pin;
char src[11],target[11];
for(int i=0;i<10;i++) dict.size = 0;
while(true){
fgets(input,50,stdin);
if(strlen(input) > 1)
input[strlen(input)-1] = '\0';
if(strcmp(input,"*") == 0) break;
len = strlen(input);
int dist;
if(dict.size[len-1] > 0){
strncpy(dict.wlist[len-1][dict.size[len-1]].words,input,len);
for(int j=0;j<=dict.size[len-1];j++){
int count = 0;
for(int k=0;k<len;k++)
if(dict.wlist[len-1][j].words[k] != input[k]) count++;
if(count == 1){
dict.wlist[len-1][j].neigh.push_back(dict.size[len-1]);
dict.wlist[len-1][dict.size[len-1]].neigh.push_back(j);
}
}
dict.size[len-1]++;
}
else{

strncpy(dict.wlist[len-1][0].words,input,len);
dict.size[len-1]++;
}
}
while(true){
fgets(input,50,stdin);
if(feof(stdin)) break;
if(strlen(input) > 1) input[strlen(input)-1] = '\0';
sscanf(input,"%s %s",src,target);
size_t srclen = strlen(src);
int srcpos = 0;
int tarpos = 0;
for(int j=0;j<dict.size[srclen-1];j++){
if(strcmp(dict.wlist[srclen-1][j].words,src) == 0){
srcpos = j;
break;
}
}

for(int j=0;j<dict.size[srclen-1];j++){
if(strcmp(dict.wlist[srclen-1][j].words,target) == 0){
tarpos = j;
break;
}
}

int bpath = search_path(&dict,srclen-1,srcpos,tarpos);
sprintf(temp,"%s %s %d\n",src,target,bpath);
output += temp;
}
cout << output;
}

Thank you in advance [/cpp]

[sohel]

Hi Juli,

I might be wrong but I don't think you are handling this program as a 'multiple input problem'. If you look closely beside the probelm name you will see a blue tick. It indicates multiple input form.

If you are a newcomer then you will find this useful.
Multiple input fomat:

N

CASE 1

CASE 2

CASE N

-- where N indicates the number of test cases.

The consecutive outputs are seperated by a blank line.

[bornagirl2397]

i used floyd to search for the shortest transformation..
but always got WA..

are there tricky inputs ??
please help me solving problem!!

code is attached below..

[cpp]
#include<cstdio>
#include<iostream>
#include<cstring>

using namespace std;

#define INFINITY 1000000

bool Trans(char *a, char *b)
{
int len,i,cnt=0;
len=strlen(a);
for(i=0;i<len;i++)
if(a!=b) cnt++;
return (cnt==1?true:false);
}

void main()
{
char dic[210][15],word1[15],word2[15];
int map[210][210]={0,};
int wordCnt=0,i,j,k,caseno;

cin>>caseno;
while(caseno--){
while(cin>>dic[wordCnt] && dic[wordCnt][0]!='*') wordCnt++;

for(i=0;i<210;i++)
for(j=0;j<210;j++)
if(i!=j) map[j]=INFINITY;

for(i=0;i<wordCnt;i++)
for(j=i+1;j<wordCnt;j++)
if(strlen(dic)==strlen(dic[j]) && Trans(dic,dic[j]))
map[j]=map[j]=1;

for(k=0;k<wordCnt;k++)
for(i=0;i<wordCnt;i++)
for(j=0;j<wordCnt;j++)
if(map[k]+map[k][j]<map[j])
map[j]=map[i][k]+map[k][j];

while(cin>>word1>>word2){
// if(word1[0]=='0') break;
for(i=0;strcmp(dic[i],word1) && i<wordCnt;i++);
for(j=0;strcmp(dic[j],word2) && j<wordCnt;j++);
cout<<word1<<" "<<word2<<" "<<map[i][j]<<endl;
}
wordCnt=0;
}
}
[/cpp]

[jaracz]

hi !
I don't see the reason I'm gettin' RTE
anyone do?

Code: Select all

#include <stdio.h>
#include <string.h>

#define MAX 201
#define LIMIT 11

char library[MAX][LIMIT];
char check[MAX][LIMIT];
char current[LIMIT];

int how;
int j = 0;
int d = 0;

int main(void)
{
    scanf("%d",&how);
    for(int a = 0; a < how; a++)
    {
        int i = 0;
        while(scanf("%s",&library[i]))
        {
            if(library[i][0]=='*')
            break; 
            i++;
        }
        i--;
        while(scanf("%s%s",&check[j],&check[j+1])==2)
        {
            j+=2;
        } 
        for(d = 0; d < j; d++){
        int quantity = 0;
        for(int a = 0; a < LIMIT; a++)
        current[a] = check[d][a];
        for(int b = 0; b <= i; b++)
        {
            int count = 0;
            for(int c = 0; c < LIMIT; c++)
            if(current[c]!=library[b][c])
            count++;
            if(count==1)
            {
                int i;
                for(i = 0; i < strlen(library[b]); i++)
                current[i] = library[b][i];
                for(i = 0; i < strlen(current); i++)
                library[b][i] = '\0';
                quantity++;
            }    
        }    
        printf("%s %s %d\n",check[d],check[d+1],quantity);
        d++;
        }    
    }   
    return 0; 
}