BFS replace an array with a map C++ - c++

Question

How to replace a common array int playersStartPos[100] with a std::map in BFS algorithm? This algorithm finds the shortest path between all two vertices. It works, but in some cases it takes more than 1 second to proceed all vertices. So I have to replace this loop for (int j = 0; j < K; j++) { //BAAAADDDDDDwith a std::map and do the search by key. But it appears it works even worse (should be better I know it 100%). How to modify an algorithm to use std::map?.
Thank you.
**INPUT**
7 3
1 1
2 0 2
2 1 4
1 4
3 2 3 5
2 4 6
1 5
0 3 6
**OUTPUT**
0 4 5
4 0 3
5 3 0
1 2
#include <iostream>
#include <stdio.h>
#include <vector>
#include <queue>
#include <map>
using namespace std;
vector<vector<int>> adjList;
int N = 0; //vertices quantity
int K = 0; //players quantity
int playersStartPos[100];
int res[100][100];
void read()
{
FILE* fp = fopen("input2.txt", "r");
fscanf(fp, "%d", &N);
fscanf(fp, "%d", &K);
for (int i = 0; i < N; i++) {
int size = 0;
fscanf(fp, "%d", &size);
vector<int> adjacency(size);
for (int j = 0; j < size; j++) {
int to = 0;
fscanf(fp, "%d", &to);
adjacency[j] = to;
}
adjList.push_back(adjacency);
}
for (int player = 0; player < K; player++) {
int pos = 0;
fscanf(fp, "%d", &pos);
//cout << pos << " ";
playersStartPos[player] = pos;
}
//fclose(fp);
}
int bfs(int start, int ind)
{
queue<int> q;
vector<bool> used(N, 0);
vector<int> path(N);
q.push(start);
used[start] = true;
path[start] = -1;
while (!q.empty()) {
int currentVertex = q.front();
q.pop();
for (size_t i = 0; i < adjList[currentVertex].size(); ++i) {
int to = adjList[currentVertex][i];
if (!used[to]) {
path[to] = path[currentVertex] + 1;
used[to] = true;
q.push(to);
for (int j = 0; j < K; j++) { //BAAAADDDDDD
if (to == playersStartPos[j]) {
res[ind][j] = path[to] + 1;
}
}
}
}
}
return 0;
}
void find()
{
for (int i = 0; i < K; i++) {
bfs(playersStartPos[i], i);
}
}
void write()
{
int min = N;
int one = 0;
int two = 0;
for (int i = 0; i < K; i++) {
for (int j = 0; j < K; j++) {
if (res[i][j] == 0) {
continue;
}
if (min > res[i][j]) {
min = res[i][j];
one = i;
two = j;
}
}
}
FILE* fp = fopen("output.txt", "w");
for (int i = 0; i < K; i++) {
for (int j = 0; j < K; j++) {
fprintf(fp, "%d ", res[i][j]);
}
fprintf(fp, "%c", '\n');
}
fprintf(fp, "%d %d\n", one, two);
//fclose(fp);
}
int main()
{
read();
find();
write();
return 0;
}
UPDATE WITH A MAP
#include <iostream>
#include <stdio.h>
#include <vector>
#include <queue>
#include <map>
using namespace std;
vector<vector<int>> adjList;
int N = 0; //vertices quantity
int K = 0; //players quantity
map<int, int> playersStartPos;
//int playersStartPos[100];
int res[100][100];
void read()
{
FILE* fp = fopen("input2.txt", "r");
fscanf(fp, "%d", &N);
fscanf(fp, "%d", &K);
for (int i = 0; i < N; i++) {
int size = 0;
fscanf(fp, "%d", &size);
vector<int> adjacency(size);
for (int j = 0; j < size; j++) {
int to = 0;
fscanf(fp, "%d", &to);
adjacency[j] = to;
}
adjList.push_back(adjacency);
}
for (int player = 0; player < K; player++) {
int pos = 0;
fscanf(fp, "%d", &pos);
//cout << pos << " ";
playersStartPos[player] = pos;
}
/*for (int i = 0; i < adjList.size(); i++) {
cout << "From: " << i << " to: ";
for (int j = 0; j < adjList[i].size(); j++) {
cout << " " << adjList[i][j];
}
cout << endl;
}*/
//fclose(fp);
}
int bfs(int start, int ind)
{
queue<int> q;
vector<int> used(N, 0);
vector<int> path(N);
q.push(start);
used[start] = true;
path[start] = -1;
while (!q.empty()) {
int currentVertex = q.front();
q.pop();
for (size_t i = 0; i < adjList[currentVertex].size(); ++i) {
int to = adjList[currentVertex][i];
if (!used[to]) {
path[to] = path[currentVertex] + 1;
used[to] = 1;
q.push(to);
for (int j = 0; j < K; j++) {
auto it = playersStartPos.find(j);
if (it == playersStartPos.end()) continue;
if (to == it->second) {
//if (to == playersStartPos[j]) {
//cout << path[to] + 1 << endl;
res[ind][it->first] = path[to] + 1;
//res[ind][j] = path[to] + 1;
//break;
}
}
}
}
}
return 0;
}
void find()
{
for (int i = 0; i < K; i++) {
bfs(playersStartPos[i], i);
}
}
void write()
{
int min = N;
int one = 0;
int two = 0;
for (int i = 0; i < K; i++) {
for (int j = 0; j < K; j++) {
if (res[i][j] == 0) {
continue;
}
if (min > res[i][j]) {
min = res[i][j];
one = i;
two = j;
}
}
}
FILE* fp = fopen("output.txt", "w");
for (int i = 0; i < K; i++) {
for (int j = 0; j < K; j++) {
fprintf(fp, "%d ", res[i][j]);
}
fprintf(fp, "%c", '\n');
}
fprintf(fp, "%d %d\n", one, two);
//fclose(fp);
}
int main()
{
read();
find();
write();
return 0;
}

Answer 1

Here it is solution
#include <iostream>
#include <stdio.h>
#include <vector>
#include <queue>
#include <map>
using namespace std;
vector<vector<int>> adjList;
int N = 0; //vertices quantity
int K = 0; //players quantity
map<int, int> playersStartPos;
int res[100][100];
void read()
{
FILE* fp = fopen("input.txt", "r");
fscanf(fp, "%d", &N);
fscanf(fp, "%d", &K);
for (int i = 0; i < N; i++) {
int size = 0;
fscanf(fp, "%d", &size);
vector<int> adjacency(size);
for (int j = 0; j < size; j++) {
int to = 0;
fscanf(fp, "%d", &to);
adjacency[j] = to;
}
adjList.push_back(adjacency);
}
for (int player = 0; player < K; player++) {
int vertex = 0;
fscanf(fp, "%d", &vertex);
playersStartPos[vertex] = player;
}
fclose(fp);
}
int bfs(int start, int ind)
{
queue<int> q;
vector<int> used(N, 0);
vector<int> path(N);
q.push(start);
used[start] = true;
path[start] = -1;
while (!q.empty()) {
int currentVertex = q.front();
q.pop();
for (size_t i = 0; i < adjList[currentVertex].size(); ++i) {
int to = adjList[currentVertex][i];
if (!used[to]) {
path[to] = path[currentVertex] + 1;
used[to] = 1;
q.push(to);
auto it = playersStartPos.find(to);
if (it == playersStartPos.end()) continue;
if (to == it->first) {
res[ind][it->second] = path[to] + 1;
}
}
}
}
return 0;
}
void find()
{
map<int, int>::iterator it;
for (it = playersStartPos.begin(); it != playersStartPos.end(); it++) {
bfs(it->first, it->second);
}
}
void write()
{
int min = N;
int one = 0;
int two = 0;
for (int i = 0; i < K; i++) {
for (int j = 0; j < K; j++) {
if (res[i][j] == 0) {
continue;
}
if (min > res[i][j]) {
min = res[i][j];
one = i;
two = j;
}
}
}
FILE* fp = fopen("output.txt", "w");
for (int i = 0; i < K; i++) {
for (int j = 0; j < K; j++) {
fprintf(fp, "%d ", res[i][j]);
}
fprintf(fp, "%c", '\n');
}
fprintf(fp, "%d %d\n", one, two);
fclose(fp);
}
int main()
{
read();
find();
write();
return 0;
}