Watering the Fields

#include <cstdio>
#include <bitset>
#include <iomanip>
#include <cmath>
#include <queue>
#include <algorithm>
#define pb push_back
#define mp make_pair
#include <iostream>
#include <queue>
#include <map>
#include <vector>
#include <string>
#define ll long long
using namespace std;

bool taken[2005][2005];

vector<pair<int,int> > g;
priority_queue< vector<int>, vector<vector<int> >, greater<vector<int> > > pq;
int x, c;

void process(int a, int b) {
    taken[a][b] = true;
    for (int i=0; i < g.size(); i++) {
        pair<int, int> pr = g[i];
        int dist = (a - pr.first)*(a-pr.first) + (b-pr.second)*(b-pr.second);
        if (!taken[pr.first][pr.second] && dist >= c) {
            vector<int> v;
            v.pb(dist);
            v.pb(pr.first);
            v.pb(pr.second);
            pq.push(v);

        }
    }
}

int a, b;
int main() {
    freopen("irrigation.in", "r", stdin);
    freopen("irrigation.out", "w", stdout);
    cin >> x >> c;
    for (int i=0; i < x; i++) {
        cin >> a >> b;
        g.pb(mp(a,b));
    }

    int dist = 0;
    process(a, b);
    while (!pq.empty()) {
        vector<int> pr = pq.top();
        pq.pop();
        int x1 = pr[1];
        int y1 = pr[2];
        int c = pr[0];
        if (!taken[x1][y1]) { dist += c; process(x1, y1);}
    }

    cout << dist << endl;
}