Narendra Narendra - 3 months ago 7
C++ Question

How to scan input from user if graph is given in form of adjancency list?

I have an input in format as shown in below Image.I am using the vector graph[200] to read input. Let's suppose program read first number of first row and column (as shown in Image) . Now I want to add all vertices which is connected to first node like graph[1].push_back(next integer in same row) and so on . But when should I stop reading input for particular Node(graph[i]). Because after reading first row I need to add vertices into another graph[i+1] to node's corresponding list . If you don't understand my questions plz have a look to my code.

#include <bits/stdc++.h>
using namespace std;

vector<int> graph[201];

int main()
{
int n=2,i,node,temp;
for(i=1;i<=n;i++)
{
cin>>node;
while(scanf("%d",&temp)!=EOF/*What is the correct conditon to stop loop*/)
{
graph[node].push_back(temp);
}
}
return 0;
}


Input format :

1 37 79 164 155 32 87 39 113 15 18 78 175 140 200 4 160 97 191 100 91 20 69 198 196
20 123 134 10 141 13 12 43 47 3 177 101 179 77 182 117 116 36 103 51 154 162 128 30
3 48 123 134 109 41 17 159 49 136 16 130 141 29 176 2 190 66 153 157 70 114 65 173 104 194 54
14 91 171 118 125 158 76 107 18 73 140 42 193 127 100 84 121 60 81 99 80 150 55 1 35 23 93
5 193 156 102 118 175 39 124 119 19 99 160 75 20 112 37 23 145 135 146 73 35
60 155 56 52 120 131 160 124 119 14 196 144 25 75 76 166 35 87 26 20
7 156 185 178 79 27 52 144 107 78 22 71 26 31 15 56 76 112 39 8 113 93
8 185 155 171 178 108 64 164 53 140 25 100 133 9 52 191 46 20 150 144 39 62 131 42 119 127 31 7
9 91 155 8 160 107 132 195 26 20 133 39 76 100 78 122 127 38 156 191 196
10 190 184 154 49 2 182 173 170 161 47 189 101 153 50 30 109 177 148 179 16 163 116 13 90 185
111 123 134 163 41 12 28 130 13 101 83 77 109 114 21 82 88 74 24 94 48 33
12 161 109 169 21 24 36 65 50 2 101 159 148 54 192 88 47 11 142 43 70 182 177 179 189 194 33
13 161 141 157 44 83 90 181 41 2 176 10 29 116 134 182 170 165 173 190 159 47 82 111 142 72 154 110 21 103 130 11 33 138 152
and so on...


Here is the screenshot of my input format

Answer

Assuming you want to read line-by-line basis, you could do following:

#include <bits/stdc++.h>
using namespace std;

vector<int> graph[201];

int main(){
    string line;
    int n=2,i,node,temp;
    for(i=1;i<=n;i++){
        getline(cin, line);
        istringstream in( line );
        in>>node;
        while(in>>temp){
            graph[node].push_back(temp);
        }
   }
   return 0;
 }