广度优先搜索_什么是广度优先搜索_广度优先搜索的优缺点 - Lane Blog


广度优先搜索_什么是广度优先搜索_广度优先搜索的优缺点 - Lane Blog
    代码将展示另一个实例。我们都玩过炸弹人的游戏,地图中有墙和敌人,在地图的空地上方一个炸弹,炸弹会在上下左右4个直线方向炸出4道火花,敌人会被炸死,而墙不会受到影响。基于此,我们用广度优先算法来实现哪个点可以炸死的敌人数量最多。
void main(){
    struct Note que[401];
    int head=1, tail=1;
    int book[20][20] = {0};
    int i, k, tx, ty, startx, starty, sum, max=0, mx, my, m, n;
    int next[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
    //地图长n,宽m,起始位置坐标为startx,starty
    scanf("%d %d %d %d", &n, &m, &startx, &starty);
    for(i=0; i<n; i++){
        printf("Line : %d", i);
        scanf("%s", a[i]);
    }
    //起点入队
    que[tail].x = startx;
    que[tail].y = starty;
    tail++;
    book[startx][starty] = 1;
    max = getnum(startx, starty);
    mx = startx;
    my = starty;
    //广度优先搜索的核心部分
    while(head < tail){
        for(k = 0; k< 4; k++){
            tx = que[head].x + next[k][0];
            ty = que[head].y + next[k][1];
            //越界
            if(tx<0 || tx>n-1 || ty<0 || ty>n-1) continue;
            //不是平地?以前走过了?
            if(a[tx][ty]!='.' || book[tx][ty]!=0) continue;
            //这个点可以走,并且没走过,就标记为走过了,然后入队
            book[tx][ty] = 1;
            que[tail].x = tx;
            que[tail].y = ty;
            tail++;
            sum = getnum(tx, ty);
            if(sum > max){
                max = sum;
                mx = tx;
                my = ty;
            }
        }
        //这个点的上下左右都看过了,就出队
        head++;
    }
    printf("炸弹放在%d,%d的位置,可以炸死%d人", mx, my, max);
}
int getnum(int i, int j){
    int x, y, sum=0;
    //统计点(i, j)的左边可以消灭多少敌人
    x = i;
    y = j;
    //如果是墙就停止
    while(a[x][y] != '#'){
        if(a[x][y] == 'G') sum++;
        x--;
    }
    //统计点(i, j)的右边可以消灭多少敌人
    x = i;
    y = j;
    //如果是墙就停止
    while(a[x][y] != '#'){
        if(a[x][y] == 'G') sum++;
        x++;
    }
    //统计点(i, j)的上边可以消灭多少敌人
    x = i;
    y = j;
    //如果是墙就停止
    while(a[x][y] != '#'){
        if(a[x][y] == 'G') sum++;
        y--;
    }
    //统计点(i, j)的下边可以消灭多少敌人
    x = i;
    y = j;
    //如果是墙就停止
    while(a[x][y] != '#'){
        if(a[x][y] == 'G') sum++;
        y++;
    }
    return sum;
}
算法八:炸弹人游戏之深度优先搜索
深度优先搜索的核心代码如下:说白了,就是一条路走到黑,然后回头倒着走看看有没有别的岔路口,不断递归。
void dfs(int x, int y){
    int next[4][2] = {{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
    int k, sum, tx, ty;
    sum = getnum(x, y);
    if(sum > max){
        max = sum;
        mx = x;
        my = y;
    }
    for(k=0; k<4; k++){
        tx = x + next[k][0];
        ty = y + next[k][1];
        //判断边界
        if(tx<0 || tx > n-1 || ty < 0 || ty > n-1) continue;
        //判断墙和是否走过
        if(a[tx][ty] != '.' || book[tx][ty] != 0) continue;
        book[tx][ty] = 1;
        dfs(tx, ty);
    }
    return;
}
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