50187. Minimum Spanning Tree, part I

#include <stdbool.h>
#include "mst.h"
 
// typedef struct mst {
//     int g[50][50];
//     int n;
// } MST;
 
void init(MST *mst, int n){
    mst->n = n;
    for(int i = 0; i < n; i++){
        for(int j = 0; j < n; j++){
            mst->g[i][j] = -1;
        }
    }
}
 
void addRoad(MST *mst, int a, int b, int len){
    mst->g[a][b] = len;
    mst->g[b][a] = len;
}
int removeRoad(MST *mst, int a, int b){
    int rtv = mst->g[a][b];
    if(rtv == -1) return 0;
    mst->g[a][b] = -1;
    mst->g[b][a] = -1;
    return rtv;
}
 
void dfs(MST *mst, int idx, int vis[]){
    for(int i = 0; i < mst->n; i++){
        if(mst->g[idx][i] == -1) continue;
        if(vis[i] == 1) continue;
        vis[i] = 1;
        dfs(mst, i, vis);
    }
}
 
bool hasPath(MST *mst, int a, int b){
    int vis[50] = {0};
    dfs(mst, a, vis);
    return vis[b] == 1;
}
 
bool connected(MST *mst){
    int vis[50] = {0};
    dfs(mst, 0, vis);
    for(int i = 0; i < mst->n; i++){
        if(vis[i] == 0) return 0;
    }
    return 1;
}