ABC - 079- A&B&C

AtCoder ABC 079 A&B&C

AtCoder - 079

A問題

• 同じ数値が連続3回以上続くかを判定
  • Aにしてはコードが長い・・・
• 多分、char[]にしてMapにputしてcountするでもよかったか

private void solveA() {
		int numN = nextInt();

		out.println(chkA(numN) ? "Yes" : "No");
	}

	private boolean chkA(int num) {

		boolean isGoodnum = false;
		int cnt = 0;
		int previous = 0;
		for (int i = 0; num != 0; i++) {
			if (i == 0) {
				//初期化
				previous = num % 10;
				num /= 10;
				cnt = 1;
			} else {
				int current = num % 10;
				if (previous == current) {
					cnt++;
				} else {
					//countやり直し
					cnt = 1;
				}
				previous = current;
				num /= 10;
			}
			if (cnt >= 3) {
				isGoodnum = true;
			}
		}
		return isGoodnum;
	}

B問題

• {$L_0=2,L_1=1$}だけ先に定義
• 後は問題どおり
• ただし、{$N=1$}の時だけ{$1$}を出力するよう分岐

	private void solveB() {
		int numN = nextInt();

		if (numN == 1) {
			out.println(1);
			return;
		}

		long val1 = 2;
		long val2 = 1;
		long res = 0;
		for (int i = 0; i < numN - 1; i++) {
			res = val1 + val2;
			long temp = val1;
			val1 = val2;
			val2 = val2 + temp;
		}

		out.println(res);
	}

C問題

• operandを$+/-$を全パターン試して合計が7になるのか調べる

private void solveC() {

		int num = nextInt();

		int[] args = convC(num);

		int[] wk = new int[4];

		int res = chkC(args, 0, wk, 0, 0);

		StringBuilder builder = new StringBuilder();
		for (int i = 0; i < wk.length; i++) {
			if (i == 0) {
				builder.append(args[i]);
			} else {
				switch (wk[i]) {
				case 1:
					builder.append("+");
					break;
				case 2:
					builder.append("-");
					break;
				}
				builder.append(args[i]);
			}
		}

		builder.append("=7");
		out.println(builder.toString());
	}

	/**
	 * 数値を配列に変換
	 * @param num
	 * @return
	 */
	private int[] convC(int num) {
		int[] wk = new int[4];
		for (int i = wk.length - 1; i >= 0; i--) {
			wk[i] = num % 10;
			num /= 10;
		}
		return wk;
	}

	/**
	 * 再帰で加減算を行う
	 * マジックナンバーだが、+ => 1/- => 2
	 * total=7になったら終了
	 * @param args
	 * @param total
	 * @param wk
	 * @param currentI
	 * @param operand
	 * @return
	 */
	private int chkC(int[] args, int total, int[] wk, int currentI, int operand) {

		if (currentI >= 4) {
			return total;
		}
		if (currentI == 0) {
			total += args[0];
		} else {
			switch (operand) {
			case 1:
				total += args[currentI];
				wk[currentI] = operand;
				break;
			case 2:
				total -= args[currentI];
				wk[currentI] = operand;
				break;
			}
		}

		int val1 = chkC(args, total, wk, currentI + 1, 1);
		if (val1 == 7) {
			return 7;
		}
		int val2 = chkC(args, total, wk, currentI + 1, 2);
		if (val2 == 7) {
			return 7;
		}

		return -1;

	}