C++ code to find minimum moves with weapons to kill enemy

Suppose we have an array A with n elements, and another number H. H is health of an enemy. We have n weapons and damaging power of ith weapon is A[i]. Different weapons can be used to kill the enemy. We cannot use same weapon twice in a row. We have to count minimum how many times we can use weapons to kill the enemy.

So, if the input is like A = [2, 1, 7]; H = 11, then the output will be 3, because if we use weapon with damage power 7, then use 2 then again use 7 we can kill the enemy.

Steps

To solve this, we will follow these steps −

sort the array A
n := size of A
x := (A[n - 1] + A[n - 2])
return H / x * 2 + (H mod x + A[n - 1] - 1) / A[n-1]

Example

Let us see the following implementation to get better understanding −

#include <bits/stdc++.h>
using namespace std;
int solve(vector<int> A, int H){
sort(A.begin(), A.end());
int n = A.size();
int x = (A[n - 1] + A[n - 2]);
return H / x * 2 + (H % x + A[n - 1] - 1) / A[n - 1];
}
int main(){
vector<int> A = { 2, 1, 7 };
int H = 11;
cout << solve(A, H) << endl;
}

Input

{ 2, 1, 7 }, 11

Output

3