Boats_to_save_people.cpp

// You are given an array people where people[i] is the weight of the ith person, and an infinite number of boats where each boat can carry a maximum weight of limit. Each boat carries at most two people at the same time, provided the sum of the weight of those people is at most limit.

// Return the minimum number of boats to carry every given person.

 

// Example 1:

// Input: people = [1,2], limit = 3
// Output: 1
// Explanation: 1 boat (1, 2)
// Example 2:

// Input: people = [3,2,2,1], limit = 3
// Output: 3
// Explanation: 3 boats (1, 2), (2) and (3)
// Example 3:

// Input: people = [3,5,3,4], limit = 5
// Output: 4
// Explanation: 4 boats (3), (3), (4), (5)



#include<bits/stdc++.h>
using namespace std;
int main(){
    int n,bl;
    cin>>n>>bl;
    vector<int> nums(n,0);
    for(int i=0;i<n;i++){
        cin>>nums[i];
    }
    sort(nums.begin(),nums.end());
    int l=0,r=nums.size()-1,c=0;
    while(l<=r){
        if(nums[l]+nums[r]>bl){
            c++;
            r--;
        }
        else{
            c++;
            l++;
            r--;
        }
    }
    cout<<c;
}