> Language:C++  Result:Wrong Answer
> 
> Source 
> 
> #include <stdio.h>
> 
> #define MAXN 5
> 
> int		fMap[MAXN][MAXN]; 
> int		n, max; 
> 
> void changeState(int fi, int fj, int num, int revert)
> {
> 	int i, j; 
> 
> 	if (revert == 0) {
> 		fMap[fi][fj] = num; 
> 		for (i = fi, j = fj + 1; j < n  && fMap[i][j] != -1; j ++) 
> 			if (fMap[i][j] == 0) fMap[i][j] = num;
> 		for (i = fi, j = fj - 1; j >= 0 && fMap[i][j] != -1; j --) 
> 			if (fMap[i][j] == 0) fMap[i][j] = num;
> 		for (i = fi + 1, j = fj; i < n  && fMap[i][j] != -1; i ++) 
> 			if (fMap[i][j] == 0) fMap[i][j] = num;
> 		for (i = fi - 1, j = fj; i >= 0 && fMap[i][j] != -1; i --) 
> 			if (fMap[i][j] == 0) fMap[i][j] = num;
> 	} else {
> 		for (i = 0; i < n; i ++) 
> 			for (j = 0; j < n; j ++) 
> 				if (fMap[i][j] == num) fMap[i][j] = 0; 
> 	}
> }
> 
> void DFS (int x, int y, int step, int tot)
> {
> 	if (tot > max) max = tot; 
> 	if (x == n) return ; 
> 	if (y == n) { DFS(x + 1, 0, step, tot); return ;}
> 	if (fMap[x][y] == 0) {
> 		changeState(x, y, step, 0); 
> 		DFS(x, y + 1, step + 1, tot + 1);
> 		changeState(x, y, step, 1); 
> 	} else 
> 		DFS(x, y + 1, step, tot);
> }
> 
> void main ()
> {
> 	char	map[MAXN][MAXN]; 
> 	int		i, j, p, q; 
> 
> 	while (1) {
> 		scanf("%d", &n); 
> 		if (n == 0) break; 
> 		for (i = 0; i < n; i ++) scanf("%s", map[i]); 
> 		max = 0; 
> 		for (i = 0; i < n; i ++) 
> 			for (j = 0; j < n; j ++) {
> 				for (p = 0; p < n; p ++)
> 					for (q = 0; q < n; q ++) 
> 						if (map[p][q] == '.') fMap[p][q] = 0;
> 						else fMap[p][q] = -1; 
> 				DFS(i, j, 1, 0); 				
> 			}
> 		printf("%d\n", max); 
> 	}
> }
> 
> //////////////////////////////////
> 
> Language:C++  Result:Accepted
> 
> Source 
> 
> #include <stdio.h>
> 
> int n , max ;
> int map[4][4];
> 
> void changeState(int fi, int fj, int num, int revert)
> {
> 	int i, j; 
> 
> 	if (revert == 0) {
> 		map[fi][fj] = num; 
> 		for (i = fi, j = fj + 1; j < n  && map[i][j] != 1; j ++) 
> 			if (map[i][j] == 0) map[i][j] = num;
> 		for (i = fi, j = fj - 1; j >= 0 && map[i][j] != 1; j --) 
> 			if (map[i][j] == 0) map[i][j] = num;
> 		for (i = fi + 1, j = fj; i < n  && map[i][j] != 1; i ++) 
> 			if (map[i][j] == 0) map[i][j] = num;
> 		for (i = fi - 1, j = fj; i >= 0 && map[i][j] != 1; i --) 
> 			if (map[i][j] == 0) map[i][j] = num;
> 	} else {
> 		for (i = 0; i < n; i ++) 
> 			for (j = 0; j < n; j ++) 
> 				if (map[i][j] == num) map[i][j] = 0; 
> 	}
> }
> 
> void find(int x , int y , int p , int tot)
> {
> 	if (tot > max) max = tot;
> 	if (x == n) return;
> 	if (y == n) { find(x + 1, 0, p, tot); return ;}
> 	if (map[x][y] == 0)
> 	{
> 		changeState(x, y, p, 0); 
> 		find(x , y + 1, p + 1, tot + 1);
> 		changeState(x, y, p, 1); 
> 	}
> 	find(x , y + 1, p, tot);
> }
> 
> int main()
> {
> int i , j , x , y;
> char a[4][5];
> 
> 	while (scanf("%d" , &n) == 1)
> 	{
> 		if (n == 0) break;
> 		for (i = 0; i < n; i ++) scanf("%s" , a[i]);
> 		max = 0;
> 		for (i = 0; i < n; i ++)
> 			for (j = 0; j < n; j ++)
> 			{
> 				for (x = 0; x < n; x ++)
> 					for (y = 0; y < n; y ++)
> 						if (a[x][y] == '.') map[x][y] = 0;
> 						else map[x][y] = 1;
> 				find(i , j , 2, 0);
> 			}
> 		printf("%d\n" , max);
> 	}
> 	return 0;
> }
> 
> 
> 

• Re:第一个程序的DFS那里多了个else，所以就不同了... (21) Bter 2006-09-19 08:09:31