sacod lab 4_2 part noorination

#include <stdio.h>

#include <string.h>

#define MAX 101



int i, j, n, c, Edges;

int g[MAX][MAX], used[MAX];



void dfs(int v)

{

    used[v] = 1;

    c++;

    for (int i = 1; i <= n; i++)

        if (g[v][i] && !used[i]) dfs(i);

}



int main(void)

{

    scanf("%d", &n); Edges = c = 0;

    memset(used, 0, sizeof(used));



    for (i = 1; i <= n; i++)

        for (j = 1; j <= n; j++)

        {

            scanf("%d", &g[i][j]);

            Edges += g[i][j];

        }



    dfs(1);

    Edges /= 2;



    if ((Edges == n - 1) && (c == n)) printf("YES\n");

    else printf("NO\n");

}