UVa 10285【搜索】

UVa 10285

哇，竟然没超时!看网上有人说是记忆化搜索，其实不太懂是啥。。。感觉我写的就是毫无优化的dfs暴力。。。。。。。

建立一个坐标方向结构体数组，每个节点dfs()往下搜就好了。

#include<iostream>
#include<cstdio>
#include<cstring>
#include<algorithm>
#define MOD 100000
using namespace std;
const int maxn = 105;
struct pos {
    int x, y;
};
pos dir[4] = { 1,0,-1,0,0,1,0,-1 };
int Map[maxn][maxn];
int vis[maxn][maxn] = { 0 };
int r, c, ans;

bool in(int x, int y, int val)
{
    if (Map[x][y]<val && !vis[x][y] && x >= 1 && x <= r&&y >= 1 && y <= c) return true;
    return false;
}

void dfs(int x, int y, int lev, int dep)
{
    ans = max(ans, dep);
    for (int i = 0; i<4; i++) {
        int nowx=x, nowy=y;
        nowx += dir[i].x, nowy += dir[i].y;
        if (in(nowx, nowy, lev)) {
            vis[nowx][nowy] = 1;
            int t = dep + 1;
            dfs(nowx, nowy, Map[nowx][nowy], t);
            vis[nowx][nowy] = 0;
        }
    }
    return;
}

int main()
{
    int N;
    cin >> N;
    char s[100];
    while (N--)
    {
        scanf("%s", s);
        scanf("%d%d", &r, &c);
        memset(vis, 0, sizeof(vis));
        for (int i = 1; i <= r; i++)
            for (int j = 1; j <= c; j++) {
                cin >> Map[i][j];
            }
        ans = 1;
        for(int i=1;i<=r;i++)
            for (int j = 1; j <= c; j++) {
                vis[i][j] = 1;
                dfs(i, j, Map[i][j], 1);
                vis[i][j] = 0;
            }
        cout << s << ": " << ans << endl;
    }
    return 0;
}