Submission #1232479

#	Time	Username	Problem	Language	Result	Execution time	Memory
1232479		nibert	Nile (IOI24_nile)	C++20	Compilation error	0 ms	0 KiB

nile

#include <iostream>
#include <vector>
#include <fstream>
#include <algorithm>
#include "nile.h"

using namespace std;

struct dsu {
    vector<int> parent, rank;
    
    dsu (int n) {
        parent.resize(n,-1);
        rank.resize(n,1);
    }
    int find(int x) {
        return(parent[x]== -1) ? x: (parent[x] = find(parent[x]));
    }
    void merge(int u, int v){
        int rootU = find(u);
        int rootV = find(v);

        if(rootU != rootV) {
            if(rank[rootU] > rank[rootV]) {
                parent[rootV] = rootU;
            }
            else if (rank[rootU] < rank[rootV]) {
                parent[rootU] = rootV;
            }
            else {
            parent[rootV] = rootU;
            rank[rootU]++;
        }
        
        }
    }
    
};

int find_best_pair(const vector<int> &w, int left, int d) {
    int low = left + 1, high  = w.size()-1;
    int best = -1;
    while (low <= high){
        int mid = (low+high) /2;
        if(w[mid]-w[left] <=d){
            if(best == -1 || w[mid] - w[left] < w[best] - w[left]) {
                best = mid;
            }
            high = mid -1;
        }
        else{
            high = mid - 1;
        }
    }
    return best;
}
int boat_count(vector<int> w, int d) {
    int N = w.size();
    sort(w.begin(), w.end());
    dsu boats(N);
    vector <bool> paired(N,false);
    for (int i = 0; i < N; i ++) {
        if(paired[i]) {
            continue;
        }
        int best_pair = find_best_pair(w,i,d);
        if(best_pair != -1) {
            boats.merge(i,best_pair);
            paired[best_pair] = true;
        }
    }
    int boat_count = 0;
    for(int i = 0; i < N; i++) {
        if(boats.find(i) == i){
            boat_count++;
        }
    }
    return boat_count;
}

int main() {
    ifstream
    file("n2.txt",ios::in);
    int n;
    file >> n;
    vector<int> w(n);

    for(int i = 0; i <n; i ++) {
        file >> w[i];
    }
    int d;
    file >> d;
    
    cout << "Number of boats if only two weights go on a boat is " << boat_count(w,d);
    return 0;
}

Compilation message (stderr)

/usr/bin/ld: /tmp/cceSX3Xt.o: in function `main':
grader.cpp:(.text.startup+0x0): multiple definition of `main'; /tmp/ccYw5Tzo.o:nile.cpp:(.text.startup+0x0): first defined here
/usr/bin/ld: /tmp/cceSX3Xt.o: in function `main':
grader.cpp:(.text.startup+0x30e): undefined reference to `calculate_costs(std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >, std::vector<int, std::allocator<int> >)'
collect2: error: ld returned 1 exit status