记忆化搜索
#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <vector>
#include <queue>
#include <algorithm>
#include <stack>
using namespace std;
#define maxn 510
#define nx x+xx[i]
#define ny y+yy[i]
int l[maxn][maxn],r[maxn][maxn];
int high[maxn][maxn];
int n,m;
bool vis[maxn][maxn];
int xx[4]={-1,0,1,0};
int yy[4]={0,1,0,-1};
int qx[maxn*maxn],qy[maxn*maxn];
inline void dfs(int x,int y)
{
vis[x][y]=true;
for (int i=0;i<4;i++){
if (nx<1 || nx>n || ny<1 || ny>m) continue;
if (high[nx][ny]>=high[x][y]) continue;
if (!vis[nx][ny])dfs(nx,ny);
l[x][y]=min(l[x][y],l[nx][ny]);
r[x][y]=max(r[x][y],r[nx][ny]);
}
}
inline int read()
{
int ret=0;
char c=getchar();
while (c<‘0‘ || c>‘9‘) c=getchar();
while (c>=‘0‘ && c<=‘9‘){
ret=ret*10+c-‘0‘;
c=getchar();
}
return ret;
}
int main()
{
n=read();
m=read();
memset(vis,false,sizeof(vis));
memset(l,0x3f,sizeof(l));
memset(r,0,sizeof(r));
for (int i=1;i<=m;i++)
l[n][i]=r[n][i]=i;
for (int i=1;i<=n;i++)
for (int j=1;j<=m;j++)
high[i][j]=read();
for (int i=1;i<=m;i++)
if (!vis[1][i]) dfs(1,i);
bool flag=false;
int cnt=0;
for (int i=1;i<=m;i++)
if (!vis[n][i]){
flag=true;
cnt++;
}
if (flag){
puts("0");
printf("%d",cnt);
return 0;
}
int left=1;
while (left<=m){
int maxr=0;
for (int i=1;i<=m;i++)
if (l[1][i]<=left)
maxr=max(maxr,r[1][i]);
cnt++;
left=maxr+1;
}
puts("1");
printf("%d",cnt);
}
原文:https://www.cnblogs.com/ainiyuling/p/11522147.html