90分(#2MLE) 求调

#include <bits/stdc++.h>
using namespace std;
int n,m,mapp[110][110];
int dx[4]={1,0,0,-1};
int dy[4]={0,1,-1,0};
int ans=1,flag,maxx,minn=1e9;
struct nod{
    int x,y,t;
};
queue<nod>q;
int bfs(int x,int y){
    nod st;
    st.t=1; st.x=x; st.y=y;
    q.push(st);
    while(q.empty()==0){
        nod now=q.front(); q.pop();
        for(int i=0;i<4;i++){
            nod nxt;
            nxt.x=now.x+dx[i]; nxt.y=now.y+dy[i];
            if(nxt.x>=1&&nxt.x<=n&&nxt.y>=1&&nxt.y<=m&&mapp[nxt.x][nxt.y]<mapp[now.x][now.y]){
                nxt.t=now.t+1;
                ans=max(ans,nxt.t);
                q.push(nxt);
            }
        }
    }
}
int main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++){
        for(int j=1;j<=m;j++){
            cin>>mapp[i][j];
            maxx=max(maxx,mapp[i][j]);
            minn=min(minn,mapp[i][j]);
        }
    }
    for(int i=n;i>=1;i--){
        for(int j=m;j>=1;j--){
            bfs(i,j);
            if(ans==maxx-minn+1){
                cout<<ans<<endl;
                return 0;   
            } 
        }
    }
    cout<<ans<<endl;
    return 0;
}