首页 > ACM题库 > HDU-杭电 > HDU 4101-Ali and Baba[解题报告]HOJ
2015
04-16

HDU 4101-Ali and Baba[解题报告]HOJ

Ali and Baba

问题描述 :

There is a rectangle area (with N rows and M columns) in front of Ali and Baba, each grid might be one of the following:
1. Empty area, represented by an integer 0.
2. A Stone, represented by an integer x (x > 0) which denote the HP of this stone.
3. Treasure, represented by an integer -1.
Now, Ali and Baba get the map of this mysterious area, and play the following game:
Ali and Baba play alternately, with Ali starting. In each turn, the player will choose a stone that he can touch and hit it. After this operation, the HP of the stone that been hit will decrease by 1. If some stone’s HP is decreased to 0, it will become an empty area. Here, a player can touch a stone means
there is path consist of empty area from the outside to the stone. Note that two grids are adjacent if and only if they share an edge.
The player who hits the treasure first wins the game.

输入:

The input consists several testcases.
The first line contains two integer N and M (0 < N,M <= 300), the size of the maze.
The following N lines each contains M integers (less than 100), describes the maze, where a positive integer represents the HP of a stone, 0 reperents an empty area, and -1 reperents the treasure.
There is only one grid contains the treasure in the maze.

输出:

The input consists several testcases.
The first line contains two integer N and M (0 < N,M <= 300), the size of the maze.
The following N lines each contains M integers (less than 100), describes the maze, where a positive integer represents the HP of a stone, 0 reperents an empty area, and -1 reperents the treasure.
There is only one grid contains the treasure in the maze.

样例输入:

3 3
1 1 1
1 -1 1
1 1 1

样例输出:

Baba Win

#include<cstdio>
#include<iostream>
#include<cstring>
#include<algorithm>
#include<vector>
#include<set>
#include<queue>

using namespace std;

const int N = 305;
int map[N][N], out[N][N], vis2[N][N];
int n, m, sx, sy, ans;
bool vis[N][N];
const int dir[4][2] = {1,0,0,1,-1,0,0,-1};
struct node {
    int x, y;
};

inline bool judge(int x, int y) {
    if(x >= 1 && y >= 1 && x <= n && y <= m) return 1;
    else return 0;
}

inline bool judged(int x, int y) {
    if(x == 1 || y == 1 || x == n || y == m) return 1;
    else return 0;
}

void bfs2(int x, int y) {
    if(vis2[x][y]) return;
    vis2[x][y] = 1;
    if(vis[x][y]) {
        out[x][y] = 1;
        return;
    }
    int i, xx, yy;
    node start, tp, p;
    start.x = x; start.y = y;
    queue<node> Q;
    Q.push(start);
    while(!Q.empty()) {
        tp = Q.front(); Q.pop();
        for(i=0; i<4; i++) {
            xx = tp.x + dir[i][0];
            yy = tp.y + dir[i][1];
            if(judge(xx, yy) && !vis2[xx][yy]) {
                vis2[xx][yy] = 1;
                if(!vis[xx][yy]) {
                    p.x = xx; p.y = yy;
                    Q.push(p);
                } else {
                    out[xx][yy] = 1;
                }
            }
        }
    }
}

void bfs() {
    if(judged(sx, sy)) {
        ans = -1;
        return ;
    }

    memset(vis, 0, sizeof(vis));
    queue<node> Q;
    node tp, p, start;
    start.x = sx; start.y = sy;
    Q.push(start);
    vis[sx][sy] = 1;
    int i, j, k, xx, yy;
    ans = 0;
    while(!Q.empty()) {
        tp = Q.front(); Q.pop();
        //printf("tp:%d %d\n", tp.x, tp.y);
        for(i=0; i<4; i++) {
            xx = tp.x + dir[i][0];
            yy = tp.y + dir[i][1];
            //printf("xx=%d, yy=%d\n", xx, yy);
            if(judge(xx, yy) && !vis[xx][yy]) {
                vis[xx][yy] = 1;
                if(map[xx][yy] == 0) {
                    if(judged(xx, yy)) {
                        //printf("%d %d\n", xx, yy);
                        ans = -1;
                        return ;
                    }
                    p.x = xx; p.y = yy;
                    Q.push(p);
                }
            }
        }
    }
    //printf("###\n");
    memset(out, 0, sizeof(out));
    memset(vis2, 0, sizeof(vis2));
    for(i=1; i<=n; i++) {
        bfs2(1, i);
        bfs2(n, i);
        bfs2(i, 1);
        bfs2(i, n);
    }
}

int main()
{
    while(cin >> n >> m)
    {
        int i, j;
        for(i=1; i<=n; i++) {
            for(j=1; j<=m; j++) {
                scanf("%d", &map[i][j]);
                if(map[i][j] == -1) {
                    sx = i; sy = j;
                }
            }
        }

        //printf("%d %d\n", sx, sy);

        bfs();
/*
        printf("\nans=%d\n", ans);
        for(i=1; i<=n; i++) {
            for(j=1; j<=m; j++) {
                printf("%d ", out[i][j]);
            }
            printf("\n");
        }
*/

        if(ans == -1) {
            printf("Ali Win\n");
            continue;
        }

        for(i=1; i<=n; i++) {
            for(j=1; j<=m; j++) {
                if(vis2[i][j] && !out[i][j]) ans += map[i][j];
                if(out[i][j]) ans += map[i][j] - 1;
            }
        }
        //printf("ans = %d\n", ans);
        if(ans % 2 == 0) printf("Baba Win\n");
        else printf("Ali Win\n");
    }
    return 0;
}

  1. 第二块代码if(it != mp.end())应改为if(it != mp.end() && (i+1)!=(it->second +1));因为第二种解法如果数组有重复元素 就不正确