[백준 17406] 배열 돌리기4

https://www.acmicpc.net/problem/17406

17406번: 배열 돌리기 4

#include <cstdio>
#include <cstring>
int R, C, K;
int board[100 + 2][100 + 2];
int ans = 0x7fffffff;

struct _st
{
	int r, c, s;
};
_st CMD[6 + 2];
int flag[6 + 2];
int choice[6 + 2];

int bak_board[100 + 2][100 + 2];
int tmp[100 + 2][100 + 2];


void input()
{
	scanf("%d %d %d", &R, &C, &K);
	for (int r = 1; r <= R; r++) {
		for (int c = 1; c <= C; c++) {
			scanf("%d", &board[r][c]);
		}
	}
	for (int i = 0; i < K; i++) {
		scanf("%d %d %d", &CMD[i].r, &CMD[i].c, &CMD[i].s);
	}
}


int rotate()
{
	// backup
	memcpy(bak_board, board, sizeof(board));

	// init
	memcpy(tmp, board, sizeof(tmp));

	for (int i = 0; i < K; i++) {
		int r = CMD[choice[i]].r;
		int c = CMD[choice[i]].c;
		int s = CMD[choice[i]].s;

		int sr = r - s;
		int sc = c - s;
		int er = r + s;
		int ec = c + s;

		while (1) {
			if (sr == er && sc == ec) break;
			for (int j = sc; j < ec; j++) tmp[sr][j + 1] = board[sr][j];
			for (int i = sr; i < er; i++) tmp[i + 1][ec] = board[i][ec];
			for (int j = ec; j > sc ; j--) tmp[er][j - 1] = board[er][j];
			for (int i = er; i > sr; i--) tmp[i - 1][sc] = board[i][sc];
			sr++; sc++;
			er--; ec--;
		}
		memcpy(board, tmp, sizeof(tmp));
	}
	// calculate
	int min_val = 0x7fffffff;
	for (int r = 1; r <= R; r++) {
		int sum = 0;
		for (int c = 1; c <= C; c++) {
			sum += board[r][c];
		}
		if (min_val > sum) min_val = sum;
	}

	// undo
	memcpy(board, bak_board, sizeof(board));
	
	return min_val;
}



void DFS(int n)	// permutation
{
	if (n == K) {
		int res = rotate();
		if (res < ans) ans = res;
		return;
	}


	for (int i = 0; i < K; i++) {
		if (flag[i]) continue;
		flag[i] = 1;
		choice[n] = i;
		DFS(n + 1);
		flag[i] = 0;
	}
}


int main()
{
	input();
	DFS(0);
	printf("%d\n", ans);
	return 0;
}

한달 전에 푼 기억이 없는데 언제풀었지 ..

암튼 가장 중요했던 것은 sr == er && sc == ec 일 때 while 문 멈춰주는 것