CareerCup

private int findMaxWeapons(int x, int y, int z) throws Exception {
        if (x > y) {
            return x - z * (x / y);
        } else if (x <= y) {
            return x - z;
        } else {
            return -1;
        }
    }

void f(){
dp[0]=w;
for(int i=0;i<=d;i++){
for ( int j = i+1; j <=d;j++){
int x = (dp[i]/c)*(j-i),y = (dp[i]%c>=j-i)? (j-i) : dp[i]%c ;
dp[j] = max(dp[j],dp[i]-x-y );
}
}
cout<<dp[d];
}

public class MaxWeapons {

  private static int getMaxWeapons(int x, int y, int z) {
    if (x < y) {
      return Math.max(x - z, 0);
    }
    int count = x;
    for (int i = 1; i <= z; i++) {
      count = count - (int) Math.ceil(((double) count) / y);
      if (count <= 0) {
        break;
      }
    }
    return Math.max(0, count);
  }

  public static void main(String[] args) {
    System.out.println(getMaxWeapons(3000, 1000, 1000));
    System.out.println(getMaxWeapons(1000, 1200, 1));
    System.out.println(getMaxWeapons(1000, 1200, 100));
  }

}

To get maximum weapons to the destination we can move all the weapons to one KM and then again full load the truck and carry. So we need to keep doing unloading/loading at 1 KM of distance.

Obvious linear time solution, not sure how to compute it faster:

x = 15
y = 3
z = 2

for i in range(z):
    if x == 0: 
        break
    x = x - (x+y-1)//y
print (x)

public static long findMaxWeapons(long X, long Y, long Z) {
        if(X <= Y)
        return X - Z;
        long wh;
        if( X % Y == 0)
        {
            if(Y % (X / Y) == 0)
            wh = Y / (X/Y);
            else
            wh = Y / (X/Y) + 1;
        }
        else
        {
            if((X % Y) % (X / Y + 1) == 0)
            wh = (X % Y)/(X / Y + 1);
            else
            wh = (X % Y)/(X / Y + 1) + 1;
        }
        if(wh >= Z)
        {
            if(X % Y == 0)
            return X - X * Z/ Y;
            else
            {
                long rem = X % Y;
                long ini = X - X * Z / Y;
                if(rem > Z)
                ini = ini + rem - Z;
                return ini;
            }
        }
        else
        return findMaxWeapons(X - (((X % Y) == 0)? X/Y : X/Y + 1) * wh , Y , Z - wh);

}

public static long findMaxWeapons(long X, long Y, long Z) {
if(X <= Y)
return X - Z;
long wh;
if( X % Y == 0)
{
if(Y % (X / Y) == 0)
wh = Y / (X/Y);
else
wh = Y / (X/Y) + 1;
}
else
{
if((X % Y) % (X / Y + 1) == 0)
wh = (X % Y)/(X / Y + 1);
else
wh = (X % Y)/(X / Y + 1) + 1;
}
if(wh >= Z)
{
if(X % Y == 0)
return X - X * Z/ Y;
else
{
long rem = X % Y;
long ini = X - X * Z / Y;
if(rem > Z)
ini = ini + rem - Z;
return ini;
}
}
else
return findMaxWeapons(X - (((X % Y) == 0)? X/Y : X/Y + 1) * wh , Y , Z - wh);
}