Binary Search : Ship packages

def CanShip (weights, max_capacity, days) :

    current_capacity = 0
    day_num = 1

    for w in weights :
        current_capacity += w

        # Current weight allotment exceeds the max_capacity, so this
        # weight may go on the ship the next day.
        if (current_capacity > max_capacity) :
            next_day_capacity = w

            # Check if this weight can never go on any ship
            # Return false and try with a bigger max_capacity
            if (next_day_capacity > max_capacity) :
                return False

            current_capacity = next_day_capacity
            day_num += 1

    # Perhaps more weights got shipped on previous days so return true and try
    # with a smaller max_capacity ship.
    if (day_num <= days) :
        return True

    return False

def FindCapacity (weights, days) :

    beg = 0
    end = 999999999 # Assume max capacity does not exceed this number.
    possible_capacity = -1

    if (len(weights) == 0) :
        return 0

    if (len(weights) == days) :
        return max(weights)

    while (beg <= end) :

        max_capacity = int(beg + (end-beg)/2)

        if (CanShip(weights, max_capacity, days)) :
            possible_capacity = max_capacity
            # Check if lesser capacity ship could be used than what has been found.
            end = max_capacity - 1
        else :
            beg = max_capacity + 1

    return possible_capacity

def main() :

    weights = [ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10 ]
    days = 5

    for days in range(1, 8) :
        print("Minimum capacity of ship for " + str(days) + " days : " + str(FindCapacity(weights, days)))

if __name__ == "__main__" :
   main()

Minimum capacity of ship for 1 days : 55
Minimum capacity of ship for 2 days : 28
Minimum capacity of ship for 3 days : 21
Minimum capacity of ship for 4 days : 17
Minimum capacity of ship for 5 days : 15
Minimum capacity of ship for 6 days : 11
Minimum capacity of ship for 7 days : 10

#include<iostream>
#include<vector>
#include<climits>
#include<algorithm>

using namespace std;

bool CanShip (vector<int>& weights, int max_capacity, int days) {

    int current_capacity = 0;
    int day_num = 1;

    for (const auto& w : weights) {
        current_capacity += w;

        /* Current weight allotment exceeds the max_capacity, so this
           weight may go on the ship the next day. */
        if (current_capacity > max_capacity) {
            int next_day_capacity = w;

            /* Check if this weight can never go on any ship */
            /* Return false and try with a bigger max_capacity */
            if (next_day_capacity > max_capacity)
                return false;

            current_capacity = next_day_capacity;
            day_num++;
        }
    }

    // Perhaps more weights got shipped on previous days so return true and try
    // with a smaller max_capacity ship.
    if (day_num <= days)
        return true;
    return false;
}

int FindCapacity (vector<int>& weights, int days) {

    int beg = 0;
    int end = INT_MAX;
    int possible_capacity = -1;

    if (weights.size() == 0)
        return 0;

    if (weights.size() == days)
        return *max_element(weights.begin(), weights.end());

    while (beg <= end) {

        int max_capacity = beg + (end-beg)/2;

        if (CanShip(weights, max_capacity, days)) {
            possible_capacity = max_capacity;
            // Check if lesser capacity ship could be used than what has been found.
            end = max_capacity - 1;
        } else {
            beg = max_capacity + 1;
        }
    }
    return possible_capacity;
}

int main() {

    vector<int> weights = {1, 2, 3, 4, 5, 6, 7, 8, 9, 10};
    int days = 5;

    for (int days=1; days<=5; days+=2) {
        cout << "Minimum capacity of ship for " << days << " days : " << FindCapacity(weights, days) << endl;
    }
    return 0;
}

Minimum capacity of ship for 1 days : 55
Minimum capacity of ship for 3 days : 21
Minimum capacity of ship for 5 days : 15

import java.util.Collections;
import java.util.List;
import java.util.Arrays;

class ShipPackages {

    boolean CanShip (List<Integer> weights, int max_capacity, int days) {

        int current_capacity = 0;
        int day_num = 1;

        for (int w : weights) {
            current_capacity += w;

            /* Current weight allotment exceeds the max_capacity, so this
               weight may go on the ship the next day. */
            if (current_capacity > max_capacity) {
                int next_day_capacity = w;

                /* Check if this weight can never go on any ship */
                /* Return false and try with a bigger max_capacity */
                if (next_day_capacity > max_capacity)
                    return false;

                current_capacity = next_day_capacity;
                day_num++;
            }
        }

        // Perhaps more weights got shipped on previous days so return true and try
        // with a smaller max_capacity ship.
        if (day_num <= days)
            return true;
        return false;
    }

    int FindCapacity (List<Integer> weights, int days) {

        int beg = 0;
        int end = Integer.MAX_VALUE;
        int possible_capacity = -1;

        if (weights.size() == 0)
            return 0;

        if (weights.size() == days)
            return Collections.max(weights);

        while (beg <= end) {

            int max_capacity = beg + ( end - beg ) / 2;

            if (CanShip(weights, max_capacity, days)) {
                possible_capacity = max_capacity;
                // Check if we can ship weights with lesser capacity than
                // what has been found.
                end = max_capacity - 1;
            } else {
                beg = max_capacity + 1;
            }
        }
        return possible_capacity;
    }

    public static void main (String[] args) {

        List<Integer> weights = Arrays.asList(1, 2, 3, 4, 5, 6, 7, 8, 9, 10);

        ShipPackages sp = new ShipPackages();

        for (int days = 1; days <= 5; days++) {
            System.out.println("Minimum capacity needed to ship within " + days + " day(s) is : " + sp.FindCapacity(weights, days));
        }
    }
}

Minimum capacity needed to ship within 1 day(s) is : 55
Minimum capacity needed to ship within 2 day(s) is : 28
Minimum capacity needed to ship within 3 day(s) is : 21
Minimum capacity needed to ship within 4 day(s) is : 17
Minimum capacity needed to ship within 5 day(s) is : 15