Description

Submission

• O(nlogn)
• the prev iterator

#include <bits/stdc++.h>

using namespace std;

vector<string> split_string(string);

/*
 * Complete the getMoneySpent function below.
 */
int getMoneySpent(vector<int> keyboards, vector<int> drives, int b) {
    /*
     * Write your code here.
     */
    int max = 0;
    sort(keyboards.begin(), keyboards.end());
    sort(drives.begin(), drives.end());
    if(keyboards[0] + drives[0] > b) return -1;
    for(auto k : keyboards) {
        auto lowerbound = lower_bound(drives.begin(), drives.end(), b - k);
        if(*lowerbound + k == b) {
            return b;
        }
        if(lowerbound == drives.begin()) continue;

        int m = k + *prev(lowerbound);
        if(m > max) max = m;
    }
    return max;
}

int main()
{
    ofstream fout(getenv("OUTPUT_PATH"));

    string bnm_temp;
    getline(cin, bnm_temp);

    vector<string> bnm = split_string(bnm_temp);

    int b = stoi(bnm[0]);

    int n = stoi(bnm[1]);

    int m = stoi(bnm[2]);

    string keyboards_temp_temp;
    getline(cin, keyboards_temp_temp);

    vector<string> keyboards_temp = split_string(keyboards_temp_temp);

    vector<int> keyboards(n);

    for (int keyboards_itr = 0; keyboards_itr < n; keyboards_itr++) {
        int keyboards_item = stoi(keyboards_temp[keyboards_itr]);

        keyboards[keyboards_itr] = keyboards_item;
    }

    string drives_temp_temp;
    getline(cin, drives_temp_temp);

    vector<string> drives_temp = split_string(drives_temp_temp);

    vector<int> drives(m);

    for (int drives_itr = 0; drives_itr < m; drives_itr++) {
        int drives_item = stoi(drives_temp[drives_itr]);

        drives[drives_itr] = drives_item;
    }

    /*
     * The maximum amount of money she can spend on a keyboard and USB drive, or -1 if she can't purchase both items
     */

    int moneySpent = getMoneySpent(keyboards, drives, b);

    fout << moneySpent << "\n";

    fout.close();

    return 0;
}

vector<string> split_string(string input_string) {
    string::iterator new_end = unique(input_string.begin(), input_string.end(), [] (const char &x, const char &y) {
        return x == y and x == ' ';
    });

    input_string.erase(new_end, input_string.end());

    while (input_string[input_string.length() - 1] == ' ') {
        input_string.pop_back();
    }

    vector<string> splits;
    char delimiter = ' ';

    size_t i = 0;
    size_t pos = input_string.find(delimiter);

    while (pos != string::npos) {
        splits.push_back(input_string.substr(i, pos - i));

        i = pos + 1;
        pos = input_string.find(delimiter, i);
    }

    splits.push_back(input_string.substr(i, min(pos, input_string.length()) - i + 1));

    return splits;
}