图的m着色问题

#include<stdio.h>/*图的m着色问题*/#define n 5#define m 4int a[n][n] = {0, 1, 1, 1, 0,1, 0, 1, 1, 1,1, 1, 0, 1, 0,1, 1, 1, 0, 1,0, 1, 0, 1, 0};int x[n+1];int sum;int ok(int k){for(int j=1;j<=n;j++)if(a[k][j] == 1 &&(x[j]==x[k]))//相邻颜色相同return 0;return 1;}void backtrack(int t){  if(t>n)  { sum++;  }  else    for(int i=1;i<=m;i++){x[t]=i;   if(ok(t))backtrack(t+1);}}int main(){    backtrack(1);    printf("%d", sum);return 0;}