Why do I get extra output in my code?

Question

This is my solution

#include <cstdio>
#include <iostream>
#include <map>
#include <vector>
#include <string>
#include <cstdlib>
using namespace std;

char a[100];
char b[100];
char c[100];
int main()
{
    int t;
    scanf("%d",&t);
    while(t--)
{
    int n;
    scanf("%d",&n);
    map <string,int> m;
    map <int,string> mrev;
    map <int,string> weight;
    vector <int> incount(5000,0);
    vector <int> to(5000,0);
    int k,i;
    for(i = 0,k = 1;i<n-1;i++)
    {
        scanf("%s",a);
        string A(a);
        scanf("%s",b);
        string B(b);
        scanf("%s",c);
        string C(c);
        int x,y;
        if(m[A]==0)
        {
            m[A] = x = k++;
            mrev[x] = A;
        }
        else
            x = m[A];
        if(m[B]==0)
        {
            m[B] = y = k++;
            mrev[y] = B;
        }
        else
            y = m[B];
        to[x] = y;
        weight[x] = C;
        incount[y] = 1;
    }
    int N = k,current;

    for(i=1;i<N;i++)
    {
        if(incount[i]==0)
        {
            current = i;
            break;
        }
    }
    int ans=0;
    while(current!=0)
    {
        printf("%s %s %s\n",mrev[current].c_str(),mrev[to[current]].c_str(),weight[current].c_str());
        string cost = weight[current].substr(0,weight[current].size()-1);
        ans += atoi(cost.c_str());
        current = to[current];
    }
    printf("%d$\n",ans);
}
return 0;
}

I'm getting the correct output for the test case but it prints an extra word in the end which I can't figure out why. This is the input and output I get

1  
5  
Warsaw Kiev 120$  
Madrid Paris 100$  
Munich Warsaw 150$  
Paris Munich 200$  
Madrid Paris 100$  
Paris Munich 200$  
Munich Warsaw 150$  
Warsaw Kiev 120$  
Kiev  
570$

while the correct output is

Madrid Paris 100$  
Paris Munich 200$  
Munich Warsaw 150$  
Warsaw Kiev 120$    
570$

I'm guessing this is something related to the IO mechanism but don't know how to fix this

I use scanf printf only to have a faster IO as told here http://stackoverflow.com/questions/18048946/why-is-scanf-printf-faster-than-cin-cout — user3542154, Sep 15 '14 at 18:37

score 0 · Accepted Answer · answered Sep 15 '14 at 18:38

No your problem is not related to IO mechanism, but break in logic. Your loop

while(current!=0)
{
    printf("%s %s %s\n",mrev[current].c_str(),mrev[to[current]].c_str(),weight[current].c_str());
    string cost = weight[current].substr(0,weight[current].size()-1);
    ans += atoi(cost.c_str());
    current = to[current];
}

for mrev[current] == "kiev" prints that value, as to[current] is equal to 0 and you have empty strings for mrev[0] and weight[0]. You may want to change condition in the loop to:

while( to[current] != 0 )

to fix this issue.

Why do I get extra output in my code?

1 Answers1