hdu FatMouse and Cheese(dp)

 

很好的一道題。先排序再dp,再開個標記數組。

 

#include #include #include using namespace std;const int INF = 0x3f3f3f3f;int dp[110][110],map[110][110];int vis[110][110];struct node{    int x,y;    int data;    bool operator < (const struct node &tmp)const    {        return data < tmp.data;    }}point[10010];int main(){    int n,k;    while(~scanf(%d %d,&n,&k))    {        if(n == -1 && k == -1) break;        int cnt = 0;        for(int i = 1; i <= n; i++)        {            for(int j = 1;j <= n; j++)            {                scanf(%d,&map[i][j]);                point[++cnt] = (struct node){i,j,map[i][j]};            }        }        sort(point+1,point+1+cnt);        memset(vis,0,sizeof(vis));        memset(dp,0,sizeof(dp));        int x,y,ans,res;        dp[1][1] = map[1][1];        res = dp[1][1];        for(int i = 1; i <= cnt; i++)        {            x = point[i].x;            y = point[i].y;            ans = -1;            for(int j = 1; j <= k; j++)            {                if(x-j>=1 && map[x-j][y] < map[x][y] && !vis[x-j][y])                    ans = max(dp[x-j][y],ans);                if(x+j <= n && map[x+j][y] < map[x][y] && !vis[x+j][y])                    ans = max(dp[x+j][y],ans);                if(y-j >= 1 && map[x][y-j] < map[x][y] && !vis[x][y-j])                    ans = max(dp[x][y-j],ans);                if(y+j <= n && map[x][y+j] < map[x][y] && !vis[x][y+j])                    ans = max(dp[x][y+j],ans);            }            if(ans == -1)            {                if(x == 1 && y == 1)                    continue;                else                {                    vis[x][y] = 1;                    dp[x][y] = 0;                    continue;                }            }            dp[x][y] = map[x][y]+ans;            res = max(res,dp[x][y]);        }        printf(%d,res);    }    return 0;}