Anonymous

#include <stdio.h>int ans[105]; int max = 0;int n, k;int black[105];    int pos = 0;char colorNode[105];char adjacent[105][105];void color(void){    int i, j;    int flag;    if( pos > max ) {        max = pos;        for( i = 0 ; i < max ; i++ )            ans[i] = black[i];    }    for(i = 1 ; i <= n ; i++) {      /* trying to color this black */        if( colorNode[i] == 1 )    /* already black */            continue;        flag = 1;        for( j = 1 ; j <= n ; j++ ) {            if( j == i )                continue;            if( colorNode[j] == 1 && adjacent[i][j] == 1 ) {                flag = 0;                break;            }        }        if( flag ) {            colorNode[i] = 1;            black[pos++] = i;            color();            pos--;            colorNode[i] = 0;        }    }}int main(){    int i, t1, t2;    scanf("%d %d", &n, &k);    for(i = 0 ; i < k ; i++) {        scanf("%d %d", &t1, &t2);        adjacent[t1][t2] = adjacent[t2][t1] = 1;    }    color();    printf("%d\n", max);    for(i = 0 ; i < max ; i++)         printf("%d ", ans[i]);    return 0;}