UVa 657 & POJ 1481 - The die is cast

传送门UVa 657 - The die is cast

题意是统计输入数据中, 每个骰子中的独立的X的个数.

关键:

1. 如何知道区分每个骰子?

对骰子进行DFS.

2.如何得到X的数目?

在骰子中对X进行DFS

因此, 这是一个DFS中包含DFS的题目.

就像求导, 先对骰子整体"求导", 再对X "求导".

详情见代码

#include <cstdio>
#include <cstring>
#include <algorithm>
using namespace std;

int ans[10000];
char in[60][60];
int num;

void DFSPoint(int x, int y);
void DFSDice(int x, int y);

int main()
{
    //freopen("input.txt", "r", stdin);
    int i, j,cases = 1, cnt;
    int row, col;
    while (scanf("%d%d", &col, &row))
    {
        getchar();
        cnt = 0;
        memset(in, 0, sizeof(in));
        memset(ans, 0, sizeof(ans));
        if (row + col == 0)
            break;
        for (i = 1; i <= row; i++)
            scanf("%s", in[i] + 1);
        for (i = 1; i <= row; i++)
        {
            for (j = 1; j <= col; j++)
            {
                if (in[i][j] == '*' || in[i][j] == 'X')
                {
                    num = 0;
                    DFSDice(i, j);
                    ans[cnt++] = num;
                }
            }
        }
        sort(ans, ans + cnt);
        printf("Throw %d\n%d", cases++, ans[0]);
        for (i = 1; i < cnt; i++)
            printf(" %d", ans[i]);
        printf("\n\n");
    }
    return 0;
}

void DFSPoint(int x, int y)
{
    if (in[x][y] != 'X')
        return;
    in[x][y] = '*';
    DFSPoint(x - 1, y);
    DFSPoint(x, y + 1);
    DFSPoint(x + 1, y);
    DFSPoint(x, y - 1);
}

void DFSDice(int x, int y)
{
    if (in[x][y] != '*' && in[x][y] != 'X')
        return;
    if (in[x][y] == 'X')
    {
        num++;
        DFSPoint(x, y);
    }
    in[x][y] = '.';
    DFSDice(x - 1, y);
    DFSDice(x, y + 1);
    DFSDice(x + 1, y);
    DFSDice(x, y - 1);
}