50变60分了，悬赏关注！！

crzcqh @ 2023-07-11 14:51:30

#include<bits/stdc++.h>
using namespace std;
int n,m; 
int a[105][105],f[105][105],vist[105][105],ans;
void dfs(int x,int y,int s){
    if(vist[x][y]) return ;
    if(x<1||x>n||y<1||y>m) return;
    if(a[x][y]<s) return ;
    if(f[x][y]) return ;
    vist[x][y]=1;
    dfs(x+1,y,a[x][y]);
    dfs(x-1,y,a[x][y]);
    dfs(x,y+1,a[x][y]);
    dfs(x,y-1,a[x][y]);//搜索四个方向
    vist[x][y]=0;
    f[x][y]=max(
        max(f[x+1][y],f[x-1][y]),
        max(f[x][y+1],f[x][y-1])
    )+1;
}
int main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin>>a[i][j];
        }
    } 
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){//每个店都做起始点遍历一遍。
            dfs(i,j,a[i][j]);
            ans=max(f[i][j],ans);
        }
    }
    cout<<ans;
    return 0;
}

by crzcqh @ 2023-07-11 14:51:59

4个点WA

by 0x282e202e2029 @ 2023-07-11 14:58:12

记忆化搜索。在搜索每个方向前先判断即可。

#include <bits/stdc++.h>
using namespace std;
const int dx[4] = {-1, 1, 0, 0}, dy[4] = {0, 0, -1, 1};
int n, m, ans;
int a[105][105], rec[105][105];
int dfs(int x, int y)
{
    if(rec[x][y])
    {
        return rec[x][y];
    }
    rec[x][y] = 1;
    int nx, ny;
    for(int i = 0; i < 4; i++)
    {
        nx = x + dx[i], ny = y + dy[i];
        if(0 < nx && 0 < ny && nx <= n && ny <= m && a[x][y] > a[nx][ny])
        {
            dfs(nx, ny);
            rec[x][y] = max(rec[x][y], rec[nx][ny] + 1);
        }
    }
    return rec[x][y];
}
int main()
{
    cin >> n >> m;
    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= m; j++)
        {
            cin >> a[i][j];
        }
    }
    for(int i = 1; i <= n; i++)
    {
        for(int j = 1; j <= m; j++)
        {
            ans = max(ans, dfs(i, j));
        }
    }
    cout << ans;
    return 0;
}

by 0x282e202e2029 @ 2023-07-11 15:00:16

@crzcqh

by crzcqh @ 2023-07-11 15:04:31

谢谢dalao!