[Round 1A 2017] Problem C. Play the Dragon (SMALL) : https://code.google.com/codejam/contest/5304486/dashboard#s=p2&a=2

Play the Dragon(SMALL).cpp

//
//  Created by fpdjsns
//  Copyright © 2019 fpdjsns. All rights reserved.
//

/*
 * 시간복잡도 : O(N^3)
 */ 
#include<iostream>
#include<vector>
#include<algorithm>
#include<queue>
#define MAX 1e9

using namespace std;

int Hd, Ad, Hk, Ak, B, D;

int getTurn(int buff, int debuff) {
	int turn = 0;

	// Debuff
	int newAk = Ak;
	int myHeal = Hd;
	for (int i = 0; i < debuff; i++) {

		if (myHeal - (newAk - D) <= 0) { // need heal
			turn++;
			myHeal = Hd - newAk;
		}

		newAk -= D;
		myHeal -= newAk;
		turn++;

		if (myHeal <= 0) return MAX;
	}

	// Buff
	int newAd = Ad;
	for (int i = 0; i < buff; i++) {
		if (myHeal - newAk <= 0) { //need heal
			turn++;
			myHeal = Hd - newAk;				
		}
		myHeal -= newAk;
		turn++;
		newAd += B;
		if (myHeal <= 0) return MAX;
	}

	// count Attack
	// return ceil((double)Hk / newAd) + turn;// need heal count
	int knightH = Hk;
	while (0 < knightH) {
		if (myHeal - newAk <= 0 && newAd < knightH) { //need heal
			turn++;
			myHeal = Hd - newAk;
		}
		knightH -= newAd;
		myHeal -= newAk;
		turn++;
		if (myHeal <= 0 && 0 < knightH) return MAX;
	}
	return turn;
}

int main() {
	int t;
	cin >> t;
	for (int c = 1; c <= t; c++) {

		int answer = MAX;
		cin >> Hd >> Ad >> Hk >> Ak >> B >> D;
		printf("Case #%d: ", c);
		
		// set Buff
		for (int i = 0; i <= 100; i++) {
			// set Debuff
			for (int j = 0; j <= 100; j++) {
				answer = min(answer, getTurn(i, j));
				if (D == 0) break;
			}
			if (B == 0) break;
		}

		if (answer == MAX) {
			printf("IMPOSSIBLE\n");
		}
		else {
			printf("%d\n", answer);
		}
	}
	return 0;
}